Sunday, 27 September 2020

Theory of quadratic equations

1) If the roots of the Equation 
x²- ax + b= 0 are real and the difference of the roots is less than 1, prove that (a²-1)/4 < b<a²/4

2) If the roots of the Equation
px² - 2px + p=0 are real and unequal, show that the roots of the Equation qx² - 2px +q= 0 are imaginary.(p,q are real)

3) If the roots of the Equation
ax² +2bx +c=0 are imaginary, show that the roots of the Equation ax²+2(a+b)x+a+2b +c= 0 are also imaginary.( a,b, c are real)

4) Show that the roots of the Equation
(1-ac)x² - (a² +c²)x - (1+ac) = 0 are real and distinct.

5) If the roots of x²-8x +a² - 6a =0 are real, show that
-2 < a < 8.

6) if  α and β are the roots of 5x²+7x+3=0, find the value of
(α³+ β³)/(1/α +1/β)

7)  If α and β  are the roots of the equation 6x² - 6x +1=0,  show that,
1/2(a+bα+cα²+dα³)+1/2(α +bβ + cβ² + dβ³)= a/1 +b/2 + c/3 + d/4

8) if one root of the equation ax²+ bx +c= 0 be n times the other the other times the other the other, prove that nb² = ac(1+n²)

9) if one root of the equation x² +(5a+3)x+(5a+2)=0 be five times the other, find the numerical value of a.

10)  if one root of the equation equation of the equation root of the equation equation of the equation the equation
px² +qx +p= 0 be the square of the other, prove that q³+2p³ = 3p²q.

11) if sum of the roots of the of the roots of the of of the roots of the of the of the x² - px +q=0 be m times their difference, show that (m² -1)p² = 4m²q.

12) if the ratio of the roots of the equation ax²+ bx+ c=0 be r, show that acr² + 2(ac - b²)r + ac = 0

13) if the ratio of the roots of roots of the equation a₁x² +b₁x+ c₁=0 be equal to the ratio of the roots equation a₂x² +b₂x+ c₂=0 prove that, b₁²/b₂² = a₁c₁/a₂c₂

14) If the difference between the corresponding roots of the equation x²+ ax+ b=0 and x² +bx +a=0 (a ≠b) is the same, find a+b.

15) if the sum of the roots of the equation equation ax² +bx +c =0 be equal to the sum of their square, show that b/c, a*b, a/c are in A.P.

16) If x₁ , x₂ are the roots of x² -3x +A=0 and x₃, x₄ are the roots of of x² - 12x +B=0 and if x₁, x₂, x₃, x₄ are in increasing GP, then find the values of A and B.

17) The constant term in the equation x²+px +q=0 is misprinted 40 for 24 and the roots are  therefore obtained as 4 and 10 find the roots of the original equation.

18) if the roots of the equation x²+6x+13=0  are p and q, find the quadratic equation whose roots are pq and p² + q².

19) If the roots of the equation x²-px+q=0 are α and β, find the equation whose roots are mα+nβ and  nα+mβ.

20)  If α and β are the roots of
2x² -3x-5=0,  find the quadratic equation whose roots are 2α+1/β and  2β + 1/α

21)  form the quadratic equation whose roots α and β satisfy the relations α²+β²=240 and αβ = 80.

22) if α and β  are the roots of the equation x²+px+q=0, show that the roots of the equation
x²+(α+β -α β)x - (α + β)αβ=0 are p and q.

23) if the equations x²-11x+a=0 and x²-14x+2a=0 have a common root, find the value of a.

24)  For what value of m the equation 3x² +4mx +2=0 and 2x²+3x-2=0 will have a common root.

25) show that the equations (b-c)x²+ (c-a)x+ (a-b) =0 and (c-a)x² +(a-b)x+ (b-c)=0 have a common root.

26) Find the condition so that the equation mx²+ x +1=0 and x² +x +m=0 may have a common root.

27) If one root of the equation ax²+bx+c=0  is the reciprocal of one root of the equation
px²+ qx +r=0, show that,
(bp - cq)(aq - br)  = (cr - ap)².

28)  Form a quadratic equation with the rational Coefficients whosr one root is 
2pq/{p+q -√(p²+q²)} , (p, q are ratiinal and p²+q² is not a perfect square)

29)  if the difference of the roots of a quadratic equation is a and the ratio of the roots be b (>1), form the equation.

30)  If one of equation
4x²+ 2x +2=0 be cosα, show that its other root is cos 3α.

31) If α and β are the roots of x²-ax+b=0 and ω,η are the roots of x² - px +q=0, find the equation whose  roots are αω+βη and αη+βω

32) If p and q are the roots of ax²+2bx+c=0, find the equation whise roots are pω+qω² and
pω²+ qω. (ω is imaginary cube root of 1)

33) if the roots of the equation x²+px+q=0 be  α ± √β, show that the roots of the equation (p² - 4q)(p²x² + 4px) - 16q=0 are 1/α ±1/√β

34) if a and x are real, show that greatest value of 2(a-x){x+√(x²+a²)} is 2a²

35) If α and β are the roots of x²+x+1=0, find the value of
α/(α+1) +  β/(1+ β)

36) In the Equation 4x²+2bx +c=0 if b= 0, find the relation between the roots of the Equation.

37) If one of the Equation x- 1/x = k is 1+√2, find the value of k.

38) If the roots α and β of ax²+2x+1=0 satisfy the relation
1/α +1/β = 1/(α +β), find the value of a.

39) Form the Quadratic Equation in x such that A. M of its roots is A and G. M is G.

40)  If α be one root of the Equation ax²+ bx+c= 0, show that one root of the Equation a²x²+ (2ac - b²)my + m²c²= 0 (m ≠0) is mα².

41) If a, b, c are real, then show that the roots of the Equation 1/(x+a) + 1/(x+b) + 1/(x+c)  = 3/x are real.

42) If α and β are the roots of the Equation x²- my - m- k=0, show that (1+α)(1+β )= 1- k, hence prove (α²+2α+1)/(α²+2α +k) +
(β²+2β+1)/(β²+2β+k)=1

43) If α, β are the roots of the Equation x²+px+q=0 and m, n of the Equation x² +rx+s= 0, evaluate
-m)(α - n)(β-m)(β-n) in terms of p, q, r, s. Hence find the condition for the existence of a Common root of the two Equations.





Friday, 18 September 2020

Revised Questions MATHS (X) ICSC-2020/21

Revised Questions (X) Maths 20/21
                            ICSC

25/11/20

1) solve: 
a) (4x²-1) -3(2x +1) +x(2x+1)= 0

b) x² - 1/x² = 29/10(x - 1/x)

c) √(x+15) = x +3, x belongs N

d) √{x(x-3)}=√10

e) √(6x-5) - √(3x -2) = 2

2) If the quotient when 3x³ - 2x²+7x-5 is divided by x+3 is given as 
3x² -11x +a. Find a.                   40           
3) If the quotient on dividing x³ - 3x² + 4x +5 by x-3 is x² - a, find a      -4

4) If a² - 3a +4 is a factor of a³+a²- la +m, find l and m.           -16, 16

5) Given that x- 1 is a factor of x²+ax +1 and show that x- a is a factor of x³ + 3x² +3x +2

6) If 2x-1, 2x-3 are the factor of 8x³+ ax² +46x+b, find a, b. Then factorise Completely.                        -36, -15

7) What should be substracted from x³ - 3x² - 10x+25 so that x-2 may be a factor

27/11/20

8)  Evaluate without consulting tables:
3 cos18/sin72. + Cosec61/sec29

9) Find the value of k given that 
3x³ + 4x² -6x +k  is divisible by x+1

10 )Use graph for this question.  Take 1cm= 1 unit on both axes.
i) Plot point P(2,3) and Q(3, 1)
ii) Reflect P in x-axis to P'. Reflect P' in y-axis axis to P". Write coordinates of P'' and P".
iii) Reflect Q in y-axis to Q' and reflect Q' in the origin to Q". write coordinates of Q' and Q". 
iv) write the geometrical name of PQQ"P'.

11) Given A= 2    0  and B= p    q
                      0    5               o     r
i) Compute A+B
ii) AB
iii) Given A+B= AB,  find the value of p, q, r.

12) Solve the inequation
- 1/3 < x/2 -4/3≤ 1/6 , x belongs to R . Graph the solution set on a number line.

13). Simplify: 
(cos 0°+ sin²45° - sin30°) ( sin90 - cos²45 + cos²60)

14) a cylindrical water tank,  base radius 1.4 metre and height 2.1 metre is filled with with the help of a pipe of radius 7cm. calculate the time(in minutes) required to fill the tank, given that water flows at the rate of 2m/s in the pipe.

15) use graph paper for this question.
Monthly wages of some factory workers are given in the following table .
with 2cm= Rs 400 starting the origin at Rs4000 and to 2cm=10 workers on the y-axis, draw the Ogive. estimate the median from the graph.
Wages in Rs.     No. Of workers.
4000-4400                8
4400-4800               12 
4800-5200               20
5200-5600               25 
5600-6000               17 
6000-6400               10


16) A point P(3,-4) is reflected in X-axis..
I) write the coordinates of P'', the image of P..
ii) PP' is joined. To which coordinates axis PP' parallel to?

17) When expression ax²+bx-6 is divided by x-1, x+1, the remainder are -10, 4.  Find a,b.

18) Given a/b= c/d, prove (2a-c)/(2a+c) = (2b-d)/(2b+d)

19) Calculate i) the Arithmetic mean ii) median iii) mode for
11,10,,11,13,13,12,15,17,14,12,13,14

20) 2/5≤ x - (1+ 2x/5)< 4/5, x belongs to R and show the number line.

21) A bus moving at its usual speed covers distance between town X and Y, which are 550km apart, in 1 hour less than it takes to cover the same distance, when it is raining and the bus has to reduce the speed by 5km/hr. Calculate the time taken to cover the distance between X and Y, when it is raining.

30/11/20
--------------
22) If A=  -2    1 and B= 2        4
                  0    3             -3        1
Find 2x2 matrix X, given that 2A-X= 3B.

23) Marks              Students 
     0-8                         5
     8-16                       3
    16-24                     10
    24-32                     16
    32-40                      4
    40-48                      2
Find mean

24) Find the value of k given that 
3x³ + 4x² -6x +k is divisible by x+1

25)Use graph for this question. Take 1cm= 1 unit on both axes.
i) Plot point P(2,3) and Q(3, 1)
ii) Reflect P in x-axis to P'. Reflect P' in y-axis axis to P". Write coordinates of P'' and P".
iii) Reflect Q in y-axis to Q' and reflect Q' in the origin to Q". write coordinates of Q' and Q". 
iv) write the geometrical name of PQQ"P'.

26) Given A= 2     0 and B= p    q
                       0     5               0    r
i) Compute A+B
ii) AB
iii) Given A+B= AB, find the value of p, q, r.

27) Solve the inequation
 - 1/3 < x/2 -4/3≤ 1/6 , x belongs to R . Graph the solution set on a number line.

28). Simplify: 
(cos 0°+ sin²45° - sin30°) ( sin90 - cos²45 + cos²60)

29) a cylindrical water tank, base radius 1.4 metre and height 2.1 metre is filled with with the help of a pipe of radius 7cm. calculate the time(in minutes) required to fill the tank, given that water flows at the rate of 2m/s in the pipe.

30) use graph paper for this question.
 Monthly wages of some factory workers are given in the following table .
with 2cm= Rs 400 starting the origin at Rs4000 and to 2cm=10 workers on the y-axis, draw the Ogive. estimate the median from the graph.
Wages in Rs. No. Of workers.
4000-4400                 8
4400-4800                12 
4800-5200                20
5200-5600                25 
5600-6000                17 
6000-6400                10

31) Using the Remainder Theorem, find the remainder when 7x²-3x+8 is divided by (x- 4).                   

32) If x²,4 and 9 are in Continued Proportion, find x.                     

33) Given A = 1    -2        B = 0
                      -3      4               1 find
a) matrix C such that A+C is zero metrix. b) find metrix D such that
   A+D =A.       c) Find AB             

34) (i) If 7 is the mean of
         5,3,0.5,4.5,b,8.5,9.5 find b.      
(ii) if each observation is decreased in value by 1 unit,what would the new mean be ?      

35) solve by formula
  (x+3)/(2x+3) =(x+1)/(3x+2).   

36) From the following table, find:
(i) The average wage of a worker, give your answer, correct to the nearest paise.
(ii) The modal class.
Wages in Rs. No of workers
Below 10            15
Below 20            35
Below 30            60
Below 40.           80
Below 50            96
Below 60.          127
Below 70           190
Below 80            200.              

37) prove.√{(1+cos x)/(1-cos x)} =
     Codec x + Cot x.     

9/12/200

1) If a: b :: c:d then prove
(a²+ac+c²)/(a²-ac+c²)= (b²+bd+d²)/(b²- bd+d²)

2) Use the proportion to solve
(2x³+6x)/(12x²+4)= 682/364

3) If x= 2ab/(a+b) then prove that [(x+a)/(x-a). + (x+b)/(x-b)]

4) Solve for x:
{√(x+4) + √(x-10)}/{√(x+4)-√(x-10) = 5/2

5) If x= {√(b+3a)+√(b-3a)}/{√(b+3a) - √(b-5a)} then prove 3ax² - 2bx + 3a = 0

6) What least number must be added to each of the numbers 16, 7, 79 and 43, so that the resulting numbers are in proportion?  

7) Using the remainder theorem, find the remainder when 7x² - 3x +8 is divided by (x -4).

8) If x², 4 and 9 are in continued proportion, find x.

9) If x belongs to Z, find the solution set for the ineqution
5 < 2x - 3 ≤ 14 and graph it on a number line.

10) Find the values of p and q if g(x)= x+2 is a factor of 
f(x)= x³ - px + x +q and f(2)= 4.

11) Given A = 1      -2           B = 0
                       -3       4                  1
i) Find a matrix C such that A + C is a zero matrix.
ii) Find the matrix D such that
 A+D = A
iii) Find AB

12) If 7th and 13th terms of an A. P be 34 and 64. Then 18th term is 

13) If the sum of pth terms of an A. P. is q and the sum of qth term is p, then sum of p+q terms will be

14) If the sum of nth terms of an A. P. be 3n²- n and its common difference is 6, then it's first term is. 
15) Sum of all two digit numbers which when divided by 4 yield as reminder is -


16) In n A. M.'s are introduced between 3 and 17 such that the ratio of the last mean to the first mean is 3:1, the value of n is.

17) The first and last terms of an A. P are 1 and 11. If the sum of its terms is 36, then the number of terms will be-


18) If the sum of n terms of an A. P is 3n²+5n then which terms is 164 ?


19) If the sum of n terms of an A. P is 2n²+5n, then find nth term.

20) In the A. P whose common difference is non-zero, the sum of first 3n terms is equal to the sum of next n terms. Then the ratio of the sum of the first 2n terms to the next 2n terms is-
21) If four numbers in A. P are such that their sum is 50 and the greatest number is 4 times the least, then the numbers are-
22) If n arithmetic means are inserted between 1 and 31 such that the ratio of the first mean and nth mean is 3:29, then the value of n is-
23) The first and last term of an A. P are a and l respectively. If S is the sum of all the terms of the A. P. and the common difference is given by
(l²-a²)/{k - (l+a)}, then find k
24) If the sum of first n even natural numbers equals to k times the sum of first n odd natural numbers, then k is
25) If the first, second and last term of A. P are a, b and 2a .Then it's sum is
26) If the first term of an A. P is 2 and common difference is 4, then the sum of its 49 terms is.
27) The number of terms of the A. P 3,7,11,15,...to be taken so that the sum is 406 is.

            
























Saturday, 12 September 2020

Revision Question for CA Foundation

Revision (mixed)
10/11/21
---------------
1) The number of ways in which nine different toys can be distributed among four children so that the youngest child gets 3 toys and each of the other gets 2 toys is
A) 2520 B)5120 C)7560 D) 9072
__________________________________

1) If a and b are whole numbers (a,b ≠1), such that aᵇ= 49 then the value (a-b)/(a+b) is
A) 5/9 B) 5  C) 9  D) n

2) evaluate: (xᵇ/xᶜ)ᵇ⁺ᶜ⁻ᵃ .(xᶜ/xᵃ)ᶜ⁺ᵃ⁻ᵇ (xᵃ/xᵇ)ᵃ⁺ᵇ⁺ᶜ
A) x⁰ B) xᵃᵇᶜ C) xᵃ⁺ᵇ⁺ᶜ. D) none

3) If 3ᵃ + 5ᵇ = 34 and 3ᵃ⁺¹+ 5ᵇ⁺¹ = 152, then the value of a and b
A)3,3 B) 5,5 C) 2,2 D) 1,3

4) If 2ⁿ - 2ⁿ⁻¹= 4, then find the value of nⁿ.
A) 8  B) 27    C) 125    D) n

5) If 4ˣ = 8ʸ, what is the value of x/y -1 ?
A) 3   B) 2   C) 0.5   D) -0.5

6) If x¹⁾³+ y¹⁾³+z¹⁾³= 0, then find the value of (x+y+z)³
A) 0   B) xyz  C) 27xyz D) n

7) If fᵃᵇᶜ = fᵃ. fᵇ. fᶜ, where a,b, c and f are all positive integers, then a²+ b²+c²=?
A) 16 B) 14 C) 18 D) 3

8) If E= 10¹⁵⁰ ÷ 10¹⁴⁶, then E+ 101?
A) 11001 B) 10101 C) 100101 D) 1000101

9) Evaluate: (0.000064)⁵⁾⁶
A) 0.0032 B) 0.00032 C)0.0000032 D) n

10) find the value of : {(p² - 1/q²)ᑫ (p-1/q)}ᵖ⁻ᑫ/{(q²-1/p²)ᑫ(q-1/p)}ᵖ⁻ᑫ
A)(p/q)ᵖ⁺ᑫ B) 1 C) p/q D) q/p

11) If E= {(x⁻¹.y²)/(x²y⁻⁴)}⁷ ÷ {(x³ y⁻⁵)/(x⁻²y³)}⁻⁵ {(x⁷⁾².y⁻¹⁾³)/(x⁵⁾².y⁻¹⁰⁾³}²⁾³. Then E+1=?
A) 3  B) 2 C) 11 D) xy+ 1.

12) if 2ˣ= 3ʸ = 6ᶻ then value of z
A) xy B) x+y C) x-y D) xy/(x+y)

13) If (a/b)ˣ⁻¹ = (b/a)ˣ⁻³, then the value of x is
A) 3   B) 2. C) 1.     D) 0

14) If Q=1/(1+ aⁿ⁻ᵐ) + 1/(1+aᵐ⁻ⁿ) the Q +1 =
A) 5     B) 2      C) 11    D) 0

15) If 2= 1pᵐ and 3= 10ⁿ, then find the value of 0.15
A)10 ⁿ⁻ ᵐ⁻¹ B) 10ᵐ⁻ⁿ⁺¹ C)10ᵐ⁺ⁿ⁺¹ D) n

16) 27ᵖ= 9/3ᵖ, then the value of 1/p² is..
A) 9   B) 4. C) 16    D) 1

17) If pᵃ = qᵇ = rᶜ and pqr= 1, then  which of the following is true ?
A) a+b+c= 0  B) a= b+c C) b= c+a
D) ab+ bc = 0

18) find the value of n, if 2ⁿ⁺¹. 5ⁿ = 200
A) 1    B) 2    C) 3    D) none

19) find the value of n, if
3⁵ⁿ. 9⁴ⁿ⁻²= 27³ⁿ⁻⁸/81⁻³ⁿ
A) 5  B) 2  C) 1  D) 5/2

20) For how many non positive values of x, the equation 4ˣ⁺¹+ 4ˣ⁻¹ equal to 17
A) 1   B) 2.   C) 0     D) 4

21) ₘ√m = (√m)ᵐ find the value of m
A) 1  B) 4     C) 1or4  D) 1 and 4

22) If x= 0.6, then find the value of [1- {1- (1-x⁵)⁻¹}⁻¹]⁻²⁾⁵.
A) 0.36 B) 0.6 C) 0.625 D) n

23) If 2ᵃ = 4ᵇ = 8ᶜ and 1/2x +1/4y +1/8z=22/7, find (x,y,z)
A)123 B) 16/7,32/7,48/7
C) 7/16,7)32,7/48  D) n

24) Simplify: (e²ˣ + e ⁻ˣ -eˣ -1)/(e²ˣ - e⁻ˣ + eˣ-1).
A) e²ˣ/(eˣ+1). B) (eˣ-1)/(eˣ +1) C) 1 D) n

25) (7.77)ˣ= (0.777)ʸ=1000, find the value of 1/x - 1/y
A)1  B) 1/3  C) 3  D) n

26) solve: (x √x)ˣ = xˣ √x.
A) 1   B) 0   C) 2   D) n

________&&

Revision Test (A. P)


1) If the 3rd and 6th terms of an AP are 7 and 13 respectively, then the first term and the common difference.                            
A) 3, 2 B) 2,3 C) 3,4 D) 43

2) sum of all natural numbers between 100 and 1000 which are multiple of 5. 
A) 90000 B)98450 C) 98500 D) n

3) how many terms of the AP -6, -11/2, -5,.... are needed to give the sum -25 ?                            
A) 5 B) 20 C) 5 or 20 D) 5& 20

4) Determine the sum of the first 35 terms of an AP if a₂ = 2 and a₇ = 22.        
A) 2000 B)2100 C) 2300 D)2310

5) If the first term of an AP is 2 and the sum of first five terms is equal to one fourth of the sum of the next five terms, then 20th term is 
A)112 B) 120 C) 210 D) 300

6) Insert 3 arithmetic mean between 2 and 10.                  
A) 1,4, 7 B) 4,6,8 C) 3,5,7, D) none

7) The sum of all odd numbers between 1 and 100 which are divisible by 3, is..
A) 83667 B) 90000 C) 83660 D) n 

8) If 7th and 13th terms of an AP be 34 and 64 respectively, then its 18th term is.
A) 87   B) 88   C) 89   D) 90 

9) If the sum of p terms of an AP is q and the sum of q terms is q, then the sum of the p + q terms will be..
A) 0    B) p-q   C) p+q   D) -(p +q)

10) If the sum of n terms of AP be n² - n and its common difference is 6, then its first term is..
A) 2    B) 3      C) 1     D) 4 

11) Sum of all two digit numbers which when divided by 4 yield Unity as reminder is..
A) 1200   B) 1210.  C)1250.  D) n

12) In n AM's introduced between 3 and 17 such that the ratio of the last mean to the first mean is 3:1, then the value of n is..
A) 6      B) 8      C) 4     D) n 

13) The 1st and last terms of an AP are 1 and 11. If the sum of its terms is 36, then the number of terms will be.
A) 5     B) 6      C) 7         D) 8 

14) If four numbers in AP are such that their sum is 50 and the greatest number is 4 times the least, then the numbers are:
A) 5,10,15,20     B) 4,10,16,22
C) 3,7,11,15       D) none

15) If the sum of the first n even natural number is equal to K times the sum of the first n odd natural numbers, then k is..
A) 1/n B) (n-1)/n  C)(n+1)/2n D)(n+1)/n  

16) If the first, second and last term of an AP are a,b and 2a respectively, then its sum is 
A) ab/{2(b-a)}       B) ab/(b-a)
C) 3ab/{2(b-a)}     D) none

17) If x is the sum of an arithmetic progression of n odd number of terms and y the sum of the terms of the series in odd places, then x/y is
A) 2n/(n+1)               B) n/(n+1)
C) (n+1)/2n               D) (n+1)/n 

18) If the first term of an AP is 2 and common difference is 4, then the sum of its 40 terms is
A) 3200 B) 1600 C) 200 D) 2800

19) The number of terms of the AP 3, 7, 11, 15, ... to be so that the sum is 406 is...
A) 5 B) 10 C) 12  D) 14   E) 20

20) If a(1/b+ 1/c), b(1/c + 1/a), c(1/a + 1/b) are in AP , then
A) a, b, c are in AP
B) 1/a, 1/b, 1/c are in AP
C) a, b, c are in HP
D) 1/a, 1/b, 1/c are in GP. 

                             
------+

Revision(A.P)
1) which term of the AP 19, 91/5, 92/5,......is the first negative term.
A) 25 B) 20 C) 15 D) 10

2) If the mth term of a given AP is n and its nth term is m then its pth term is..
A) n+m+p B) n+m-p C) n-m+p D) n-m-p

3) 15th term from the end of the AP 3, 5, 7, 9,.....201 is
A) 100 B) 152 C) 173 D) 194

4) The sum of all odd integers from 1 to 1001 is
A) 250000 B) 250001 C) 251000 D) 251001

5) 1+6+11+....+x=148. Then x is
A) 36 B) 30 C) 26 D) 20

6) Find the sum of 32 terms an AP whose 3rd term is 1 and 6th term is -11.
A) 1696 B) -1696 C) 1876 D) -1876

7) If the sum of n terms of an AP is (3n²+ 5n) and it's mth term is 164, then value of m is
A) 22 B) 25 C) 27 D) 29

8) Arithmetic mean between (a-b) and (a+b) is
A) ab B) b C) 1/ab D) a

9) There are five numbers between 8 and 26. Find the 4th term
A) 17 B) 20 C) 13 D) 11

10) The sum of first 7 terms of an AP is 10 and that of next 7 terms is 17. Find the 2nd term
A) 1 B) 8/7 C) 9/7 D) 10/7

11) The sum of all natural numbers lying between 100 and 1000, which are multiple of 5 is.
A) 98000 B) 98700 C) 98450 D) n

12) Number of terms needed for the series -6, -11/2, -5,....to give the sum -25
A) 5 B) 10 C) 16 D) 20



Revision Test (S. I & C. I)

1) Amount due in 3 years on ₹5000, when the rate of compound interest for successive years is 6%, 8%, 10% respectively.
A) 6240.96           B) 6296.40.
C) 5790                 D) 7690.40

2) A sum of ₹9600 is invested for 3 years at 10% p.a at compound interest. Find the difference between the intrest of second and first year.
A) 1000 B) 1056. C) 1100 D) 1200

3) The simple interest on a certain sum computes to ₹400 in 2 years and the compound interest on the same sum at the rate and for the same time computes to ₹410. Find the rate per cent.
A) 2% B) 3% C) 4 % D) 5%.

4) A certain sum of money, placed at compound interest amount to ₹6272 in 2 years and to ₹7024.56 in 3years. Find the rate of interest
A) 10% B) 12%. C) 14% D) 15%

5) A certain sum of money, placed at compound interest amount to ₹6272 in 2 years and to ₹7024.56 in 3years. Find the sum of money
A) 5000. B)10000 C) 15000 D) 4000
-----------------------------




8/8/21
1) If ⁿP₅ = 20x ⁿP₃, then n is
A) 8.      B) 10  C) 12  D) 14

2) In how many ways can 5 persons occupy 3 vacant seats?
A) 60.  B) 72 C) 120 D) 420

3) σₓ² = 2.25, σᵧ²= 1 and Cov(x,y)= 0.9 then  rₓᵧ is..
A) 0.1 B) 0.3 C) 0.4  D) 0.6.

4).  X           Y
      92        86
      89        83
      86        77 
      87        91 
      83        68 
      71        52 
      77        85 
      63        82
      53        57 
      50        57 then rank correlation
A) 0.715. B) 0.517 C) 0.175 D) 0.75

5) If f(x)= (x+1)/(x-1), x≠1, then (fofofof) is...
A) 1/x B) x. C) x² D) indeterminate

6) If f(x)= 2x -1, when x ≤ 0
                   x², when x > 0 
then f(-1/2) is
A) 2  B) -1/2 C) -2. D) 1/2

7) At what rate percentage simple interest, would a sum double itself in 6 years ?
A) 15%  B) 16% C) 50/3%. D) none

7/7/21
1)  sasank walks 20m in front and 20m to the right. Then every time turning to his left, he walks 10, 20, 20m respectively. How far is he now from his starting point?
A) 10m B) 20m C) 20m D) 25m E) n

2) L.C.M of 3!, 6!, 8!.
A) 40320.B) 43200 C) 30420 D) n

3) If bᵧₓ = 1.4 and bₓᵧ = 0.3 then r is
A) 1 B) 0.56 C) 0.65. D) none

4) If ∑ D²= 33 and N= 10, then R is
A) 0.7 B) 0.8. C) 0.9 D) 1

5) A sum of ₹800 amounts to 920 in 3 years at simple interest. If the interest rate is increased by 3%, it would amount to ..
A) 929 B) 992. C) 299 D) none 

6) The compound interest, calculated yearly, on a certain sum of money for the second year is ₹880 and for the third year it is ₹968. Then the rate is..
A) 10% B) 20% C) 15% D) 25% 

7) Given f(x)= 3x², g(x)=2x+3 then {f(-2)+ g(-3)}/{g(-2)+ f(-3)} is..
A) 1/8   B) 12/8   C) 15/8.  D) n 

8) How many numbers greater than a million can be formed with the digits 2,3,0,3,4,2,3 ?
A) 60  B) 360.   C) 420    D) 1020



1) Five boys and three girls are seated at random in a row. The probability that no boys sits between two girls is:
A) 1/56. B)1/8. C)3/28. D) none

2) Two cards are drawn at random from a pack of 52 cards. The probability of getting at least a spade and an ace is:
A) 1/34 b)8/221 c)1/26. D) 2/51

3) A five digits number is written down at random. The probability that the number is divisible by 5 and no two consecutive digits are identical, is
A) 1/5. B)1/5 .(9/10)³ c)(3/5)⁴ d)N

4) If the letters of the word ATTEMPT are written down at random, the chance that all Ts are consecutive.
A)1/42 b)6/7. C) 1/7. D) none

5) In a single cast with two dice the odd against 7 is
A)1/6. B)1/12. C)5:1. D) 1:5

6) 7 white balls and 3 black balls are placed in a row at random. The probability that no two black balls are adjacent is:
A) 1/2. B)7/15. C)2/15. D) 1/3

7) 10 apples are distributed at random among 6 persons. The probability that atleast one of them will receive none is:
A)6/143                   b)14C4/15C5
c)137/143.              D) none

8) 4 gentleman and 4 ladies take seats at random round a table. The probability that they are sitting alternatively is
A)4/35. B)1/70. C)2/35. D)1/35

9) Three dice are thrown simultaneously. The probability of getting a sum of 15 is
A)1/72. B)5/36. C)5/72 d) none

10) Three dice are thrown. The probability of getting a sum which is a perfect square is:
A)2/5. B)9/20. C)1/4. D) none

11) Three different numbers are selected at random from the set A={1,2,3,...10}. The probability that the product of two of the numbers is equal to the third is
A)3/4. B)1/40. C)1/8. D) none

12) solve 
A) 3x² - x -7=0 and give your answer Correct to 2 decimal places.

B) solve: (4x²-1) - 3(2x +1) + x(2x+1)= 0

C) x² - 1/x² = 29/10(x - 1/x)

D) √(x+15) = x +3, x belongs N

E) √{x(x-3)}=√10

F) √(6x-5) - √(3x -2) = 2
 
13) If y= f(x)= (x+1)/(x+2) prove that f(y)= (2x+3)/(3x+5)

14) f(x)= x⁹-6x⁸ -2x⁷ +12x⁶ +x⁴ -7x³ +6x² +x -3 then find the value of f(6).

26/11//20
--------------


16) If A = 0 2 3 And B= 7 6 3
               2 1 4 1 4 5
Find the value of 2A +3B

17) prove by determinant
 1 x x²-yz
 1 y y²-zx = 0
 1 z z²-xy

18) If y= (x+√(x²-1)ᵐ prove that (x²-1)(dy/dx)²= m²y²

19) If f(x)= (x-1)/(2x²-7x+5) when. X≠1 and f(x)= -1/3 when x=1, find f'(1)

20) you are given the following results on two variables x and y: mean of x and y are 36, 85 S.D of x and y are 11, 8 covariance of x,y is 0.66. find the two regression equation and estimate the value of x when y=25.


21) Find X and Y, if X+Y = 7 0 
                                              2 5
And X - Y = 3 0  
                    0 3
 

22) Solve for x: x 1 1
                             1 x 1 = 0
                             1 1 x 
With the help of DETERMINANT.

23) Given A= 1 2 and B= 4 5
                        2 3 5 6
Calculate AB and BA


24) If A= 1 2
                2 1 , show that
A² - 3I= 2A,



25) Prove with the help of DETERMINANT 9 9 12
                              1 -3 -4 = 0
                              1 9 12

26) Find the value of x,y,z of
              x+y+z 9 
                   z+x = 5
                   y+z 7

27) If x= t log t, y=( log t)/t , then find the value of dy/dx at t=1

28) If A= 1 0 and I= 1 0
             -1 7 0 1 then find K so that A² = 8A + KI

29) Without expanding the determinant prove that
    a a² bc 1 a² a³
    b b² ca = 1 b² b³ 
    c c² ab 1 c² c³


30) Find the symmetric part of the matrix A = 1 2 4
                    6 8 2
                    2 -2 7


31) If P= 1 k 3
                1 3 3
                2 4 4 
is the adjoint of a 3x3 matrix A and | A|= 4, then find the value of k.

32) Finf dy/dx of log₍₂ₓ₋₃₎(x² - 2x)

33) If A= 1 x 1      

   B= 1 3 2 1
          0 5 1 C = 1
          0 3 2 x
If A.B.C= 0 , then find x

34) If f(x)=x²+2x+7, find f′(3)

35) If xʸ + yˣ = aᵇ, find dy/dx.

36) If (3x⁴-2x+6)⁴(x-3)²⁾³ find dy/dx

37) If A= 2 -1
                 1 2
 then Find A² +2A - 3I

38) If A= 1 3 0 and B= 1 3 
                2 1 4 0 2
                                           -2 -1
 find AB

39) Find the value of x, y,z from the equation 4 x-z = 4 3
                       2+y xz -1 10  

40) Without expanding at any stage, find the value of the determinant:
 2 x y+z
 2 y z+x 
 2 z x+y

41) Find k if M= 1 2
                             2 3   
and M² - kM - I₂ = 0

42) Find dy/dx, if x= at² & y= 2at

43) By using property of Determinant prove x x² 1+px³ 
                                      y y² 1+py³ 
                                      z z² 1+ pz³
= (1+pxyz)(x-y)(y-z)(z-x)

44) Evaluate A= 3 -2 3
                             2 1 -1
                             4 -3 2 and 
B= -1 -5 -1
      -8 -6 9
     -10 1 7 as AB. 

45) If the lines of Regression are 4x+2y -3= 0 and 3x+ 6y +5=0, find the correlation coefficient between x and y.

46) Find the regression coefficients of x on y and y on x
X: 2 6 4 7 5 
Y: 8 8 5 6 2










Friday, 11 September 2020

Complex Number

COMPLEX NUMBER

1) If x= 2+ 3i and y= 2-3i, find the value of (x³-y³)/(x³+y³)
a) 1.  b) -9i/46 c) i.        d) none

2) 20/(√3-√-2) + 30/(3√-2-2√3) + 14/(2√3-√-2)
A) 0.    B) 1.     C) 2.    D) 3

3) (cos30°+isin30°)⁴/(cos20°+isin60°)²
A) 0.  B) 1.  C) 2.      D) none

4) If {(1+i)/(1-i)}³ - (1-i)/(1+i)}³ = p+iq, find (p,q)
A) 0,0.  B) 0,1. C) 1,2.   D) 0,-2

5) If x=1+3i then find the value of x⁴-5x³+18x²-34x+2
A) -20.  B) -30.    C) -18.    D) -32

6) If x= -5+2√-4, find the value of x⁴+9x³+35x²-x +4
A) 160. B) -160. C) 200 d) -200

7) If x=2+i, then x³-5x²+9x-5 is
A) 0.65   b) 0.66.  C) 0.67.   D) 0.68

8) Find the modulus of:
A) 2/(4+3i) - 1/(3-4i)
B) {(2-3i)(√5+2i)}/3i(3-2i)

9) if z₁= (√3 -1) + (√3 +1)i and 
z₂= -√3 +i, find amp z₁ , amp z₂ and (z₁z₂)

10) If z= sin 6π/5 + i(1+ cos 6π/5), find |z| and amp z.

11) If z= x+iy and 2|z -1|= |z-2|, show 3(x²+y²)= 4x

12) If arg {(z-2)/(z-4i)}= π/4, show that the locus of z in the cimplex plane is a circle.

13) Find the square root of...
a) 9i          b) 1+ 2√(-6)
c) y+√(y²-x²)
d) a² + 1/a² + 2(a+ 1/a)i + 1
e) √(28) + i √(147)

14) Show that
a) √(1+i) +√(1-i)=√(2(√2+1))
b) √(2+i3√5)= 3√(2)
c) (19 + 5√-24)¹⁾² - (19 -5√-24)¹⁾² =2√(-6)
d) (4+ 3√-20)¹⁾² + (4- 3√-20)¹⁾²=6

15) If ω be an imaginary cube root of 1, show that
a) (1-ω²)(1-ω⁴)(1-ω⁸)(1-ω¹⁰)=9
b) 1/(1+ 2ω) - 1/(1+ω) + 1/(2+ω) =0
c) (x+yω+zω²)⁴+(xω+yω²+z)⁴ +(xω²+y+zω)⁴ =0

16) If a= cosθ +i sinθ, prove that, 1+ a+ a² = (1+2cosθ)(cosθ+ isinθ).

17) If √(a+ bi + ci² + di³)= p+iq, prove (p²+ q²)²= (a-c)² + (b-d)²

17) Ley z₁= a+ ib and z₂ = p +iq be two complex numbers such that Iₙ= (z₁ ⃗z₂)=1. If ω₁=a+ip and ω₂= b + iq, show that Iₙ=(ω₁⃗ω)=1

18) If x¹⁾³=ωα¹⁾³+ ω²b¹⁾³(ω is an imaginary cube root of unity), show that, (x-a-b)³=27abx

19) Show that the conjugate complex number of (1+i)⁵ is -4(1-i)

20) Express (a+bi+ci²+di³)/(a-bi-ci²+di³)    (a,b,c,d ate real) in the form of A+iB(A, B are real)

21) If the complex number (sin x + icos 2x) and (cosx - isin2x) are conjugate to each other, then (A)x= np(B)x= (n + 1/2)π (C)x= 0 (D)x has no value. choose the correct answer.

22) z₁ and z₂ ate two complex number such that z₁ ≠ z₂ and |z₁|. show that the real part of (z₁+z₂)/(z₁-z₂) is zero.

23) The moduli of three complex numbers x,y,z are equal. if x+y+z=0, then prove that, 1/x +1/y+ 1/z=0

24) If m= x+iy and M= X + iY, prove that, x²+ y²={(X²-1)²+Y²}/{(X²+1)²+Y²}, where m= (M-1)/(M+1)

25) If the value of (3+2isinx)/(1-2isinx) is (a) purely real (b) purely imaginary, find the value of x in both cases

26) Express (1+sinx+icisc)/(1+sinx-icosx ) in the form of A+ iB and hence the argument.

27) Show that (cosπ/10+ isinπ/10) (cos2π/10+ isin2π/10)(cos3π/10+isin3π/10)(cos4π/10 + isin4π/10) = -1

28) If a= cosx + I sinx and 1+ √(1-b²) = nb, then prove that
(1+na)/2n. (1+ n/a)= 1+ b cosx.

29) If z₁ and z₂ are two complex numbers, prove that
a) |z₁+√(z₁²-z₂²)|+|z₁-√(z₁²-z₂²)| =
|z₁+z₂| +|z₁-z₂|
b) |1- ⃗z₁z₂|² - |z₁ -z₂|²=
(1-|z₁|²)(1-|z₂|²)

30) If iz³+ z² - z +i =0, show that |z|=1

31) z₁, z₂, z₃ are three complex numbers. prove that, z₁Iⱼ( ⃗z₂z₃) + z₂ + Iⱼ (⃗ ⃗z₃ z₁) + z₃ Iⱼ ( ⃗z₁ z₂)= 0 where Iⱼ(W) = imaginary part of W, where W is a complex number.

32) z₁= a+ ib and z₂= c + id are two complex numbers such that
|z₁|=|z₂|=1 and Rₑ(z₁z₂)=0, show that the two complex numbers ω₁=a+ ic and ω₂= b+ id are such that |ω₁|= |ω₂|= 1 and Rₑ (ω₁ω₂)=0

33) If z = x+iy, then show √2 |x+iy| ≥
|x| + |y|

34) Let z₁= 10+ 6i and z₂= 4+ 6i. If z be a complex number such that arg[(z - z₁)/(z-z₂)]= π/4, then prove that, |z-7 - 9i| =3√2

35) If (a₁ +ib₁)(a₂ +ib₂)(a₃ +ib₃)...(aₙ+ibₙ) prove that
a) (a₁² + b₁²)(a₂²+ b₂²)(a₃²+b₃²)... (aₙ²+ ibₙ²)= A²+ B²
b) tan⁻¹(b₁/ a₁) +tan⁻¹(b₂/a₂)+ tan⁻¹(b₃/a₃) ......+ tan⁻¹(bₙ/aₙ) =tan⁻¹(B/A)

36) If W= √(z²-1) and z= x+iy, show amp W= 1/2[tan⁻¹(y/(x+1) +
tan⁻¹(y/(x-1)]

37) If the complex number z satisfies the equations
|(z-12)/(z-8i)|= 5/4 and |(z-4)/(z-8)| = 1, find the value of z

38) If z be a compkex number, solve the equation z² + |z| = 0

39) If α²+α+2, show x³-1= (x-1)(y-α) (x-α²)

40) Show (y-z)² + (z-x)² + (x-y)²= 2(x+yω+zω²)(y+yω²+zω), where ω is an imaginary cube root of 1

41) If α be the real cube  root of β, η be the complex cube roits of m, where m is positive real number, then for any a, b, c, show that, (aβ+bη+cα)/(aη+bα+cβ) =ω², where ω is a complex cube root of unity.

42) find value of {-1+i√3)¹⁶/(1+i)²⁰} + {-2-i√(3)¹⁶/(1-i)²⁰}

43) show{(-1+√-3)/2)}ⁿ+{(-2-√-3)/2}ⁿ = 2 when n isbpositive integers and multiple of.3.
= -1 when n is any other positive integer.

44) If ω be a complex cube roit of unity, find the value of 1.(2-ω)(2-ω²) + 2.(3-ω)(3-ω²)+...+(n-1)(n-ω)(n-ω²)

45) If ω be an imaginary cube root of unity and x= a+ bω + cω², show that  x³-3ax²+3(a²-bc)x=a³+b³+c³-3abc

46) if x= a+ bω+cω², y= aω+bω² +c, z= aω²+ b + cω, show that x²/yz + y²/zx + z²/xy = 3

47) z₁, z₂, z₃ are three complex numbers such that, z₁+ z₂+ z₃= A,
z₁+ z₂ω+z₃ω²= B and
z₁ +z₂ω²+z₃ω= C, where ω is an imaginary cube root of 1. prove
|A|²+ |B|²+ |C|²= 3{|z₁|²+|z₂|²+|z₃|²

48) If x= α² + 2βη, y=β²+2ηα,
z = η²+2αβ prove that (α³+β³+η³-3αβη)= x³+y³+z³- 3xyz

49) If a and b are real numbers between 0 and 1 and the points represented by complex numbers z₁= a+ i, z₂= 1+bi and z₃ =0 form an equilateral triangle in the complex plane, then find the values of a and b.

50) If m be real, n= u+ iv, z= x+iy and ⃗n⃗,  ⃗z conjugate of n and z respectively, then show that the equatiin n( z+ ⃗z)+ ⃗n(⃗z - z) + m=0 represents two straight lines in the complex plane. Find the angle between the straight lines.

51) W= (z+1)/(z-1), where z is a complex number. If z lies on the circle |z - 1|= 2, show that W lies on a circle in the complex plane. Find the centre and radius of that circle.

52) Show that the area of the triangle formed by three complex numbers z, iz and (z+iz) in the complex plane is 1/2 |z|².

53) If the area of the Triangle formed by the complex numbers z, iz and z+ iz is ar² , where |z| = r, then find the value of the constant a.

54) If P,Q,R represent the complex numbers z₁, z₂, z₃, respectively in the complex plane and lz₁+mz₂+n z₃ =0 when l+m+n=0, show that P, Q, R are collinear.

55) If the complex number z satisfies the Equation|z - 6/z|= 2, find the greatest value of |z|.

56) Find the least value of|z + 1/z|, if |z| ≥ 2.

57) In the complex plane the condition |z + 2/z|=2 is satisfied by the moving point which is represented by the complex number z (≠0). Find the maximum distance of the point from the origin.

58) Show that the three cube roots if I, are - I, (I+√3)/2, (i-√3)/2

59) If z= 1+ sinx + I cosx, find amp z

60) If z= 1+ cos2x + isin2x,
π/2<x<3, π/2 find amp. z

61) If az+ ib ⃗z = 0, where z= x+ iy and a+b ≠0, find the value of x+y

62) If z₁, z₂ are conjugate of each other anf z₃, z₄ are conjugate of each other, show that , amp z₁/z₄ = amp. z₃/z₂.

63) show that, amp (z) - amp (-z)
       =π, when amp(z) > 0
      = -π when amp (z) < 0

64) Explain with reasons which one of the following is correct?
A) 2 + 3i > 1+ 4i
B) 6+2i > 3+ 3i
C) 5+ 8i > 5+ 7i
D) none of these (i² = -1)

65) If |z₁|=| z₂ |= 1 and
amp z₁ + amp z₂ = 0, prove that
z₁z₂ = 1

66) If the complex number z= x+ iy satisfies the Equation
|(z-5i)/(z+5i)| = 1, then z lies on
A) the x-axis.        B) the line y=5
C) a circle passing through the origin

67) Solve: |z| + z= 1 +3i, where z is a complex number.

68) For any complex number z the minimum value of |z| + |z -1| is
A) 1. B) 0.  C) 1/2.   D) 3/2









* Three complex numbers are in A P. Show that they can not be on a circle in the complex plane.
** Prove that two complex numbers z₁ and z₂, which are not zero form an equilateral triangle with the origin in the complex plane if z₁²- z₁z₂ + z₂² = 0.
***Show that the origin and the points in the complex plane which are represented by the roots of the Equation x²+pz+q= 0 form an equilateral triangle if p²= 3q.
*** If the vertices A,B,C of a right angled isosceles triangle, right angled at C, are represented by complex numbers z₁, z₂, z₃, respectively, then show that
(z₁- z₂)² = 2(z₁- z₃)(z₃ - z₂).
** Three complex numbers z₁, z₂, z₃, are such that |z₁|=|z₂|=| z₃| and they represent the vertices of an equilateral triangle in the complex plane; show that z₁+z₂+ z₃=0






Friday, 4 September 2020

Trigonometrical Ratios and identities

    Trigo Ratios and Identity

Prove
1) (sin⁸x - cos⁸x)= (sin²x-cos²x)(1 - 2sin²x cos²x)

2) (secA -tanA)/(secA+ tanA)= 2secA tanA + 2tan²A)

3) (cosα cscα- sinα secα)/(cosα+sinα)= (cscα - secα)

4) (1-cotα - cscα)(1+tanα+secα)=2

5) (cscα -sinα)(secα -cosα)(tanα+cotα)= 1

6) {cot²α(secα -1)}/(1+sinα) =sec²α . (1-sinα)/(+secα)

7) (secx+  -tanx)/(tanx -secx+1)= (1+cosx)/sinx

8) If tₙ = sinⁿx + cosⁿx, show that (t₃ -t₅)/t₁  = (t₅ -  t₇)t₃

9) (sinα + cscα)²+(cosα +secα)² = tan²α + cot²α +7

10) (1+cotα +tanα)(sinα - cosα) = secα/csc²α   - cscα/sec²α

11) {2sinα tanα(1-tanα)+ 
2sinα sec²α)}/(1+tanα)² = 2sinα/(1+tanα)

12) (tanα +cscx)² -(cotx -secα)² = 2tanα cotx (cscα+ secx)

13) {(1+sinα -cosα)/(1+sinα+cosα)}²=(1-cosα)/(1+cosα)

14) 2sinα/(1+sinα+cosα)=x, then
(1-cosα+sinα)/(1+sinα) is also x

15) {1/(sec²α-cos²α) + 1/(csc²α-sin²α)} (sin²α cos²α) = (1-sin²αcos²α)/(2+sin²α cos²α)

16) (cscx -secx)(cotx-tanx)=(cscx+secx)(secx cscx -2)

17) 3[sin⁴(3π/2 - x)+ sin⁴(3π+x)] 
   - 2[sin⁶((π/2 +x)+ sin⁶(5π-x)]
a) 0   b) 1 c) 3 d) sin 4x+sin 6x e) n

18) 3(sin x - cos x)⁴+6(sinx + cosx)² + 4(sin⁶x + cos⁶x) is
a) 1     b) 0     c) 2      d) none

19) If sin x + cos x= a, then find the value of |sinx - cosx|
a) a     b) -a     c) ±a    d) none

20)  If sin x + cos x= a, then find the value of sin⁴x - cos⁴x
a) 1   b) 0       c) a²  d) a⁴    e)  none

21) If sin a + cosec a= 2 then sin²a + cosec²a is
a) 2    b)  -2    c) ±2    d) none

22) (secA + tanA -1)(secA - tanA+1) - 2tanA simplify
a) 0     b) 1   c) -1    d) sinA  e) n

23) If sinx + sin²x= 1 then find the value of cos¹²x+ 3cos¹⁰x+ 3cos⁸x + cos⁶x - 1
a) 0      b) 1      c) 2        d) none

24) If sinx + sin²x + sin³x=1 then cos⁶x - 4cos⁴x + 8 cos²x is
a) 0    b) 1    c) 2      d) 3       e) 4

25) sec⁴A(1- sin⁴A) - 2tan²A = ...
a) 0     b) 1   c) 2       d) none

26) If tanA+ sinA= m, tanA- sinA=n then show m²-n²= 4√(mn)

27) if cosx + sinx =√2  cosx prove cos x - sin x= √2 sin x

28) If 3sinθ +5cosθ=5, prove that 
    5 sinθ - 3cosθ= ±3

29) If a cosθ+ bsinθ= p, 
     asinθ- b cosθ= q, prove that a²+b² = p²+q²

30) If acosx - b sinx = c, show that adinx+bcosx= ±√(a²+b²-c²)

31) If a sinx + b cis x = c, show that (a-b tanx)/(b+atanx)= ±√(a²+b²-c²)/c

32) If tan²x= (1 -m²) show that secx+ tan³x cosrcx= (2-m²)³⁾²

33) ax/cosθ + by/sinθ = (a²- b²), and axsinθ/cos²θ - bycosθ/sin²θ
 =0 show that
(ax)²⁾³ +(by)²⁾³ = (a² - b²)²⁾³

34) If secx= p+ 1/4p, then secx + tan x= 2p or 1/2p

35) If secx + tan x = p find the value of secx, tanx, sinx in terms of p.

36) cosα/cosβ = a, sinα/sinβ= b, then (a² - b²)sin²β= a² - 1

37) If tanθ= p/q, show that
(psinθ- qcosθ)/(psinθ+ qcosθ) = (p²-q²)/(p²+q²)

38)
* Eliminate x from the following:
1) a sec x= 1 - b tan x and 
a²sec² x= 5+ b² tan²x

2) cscx - sinx=m , secx - cosx=n

3) cscx - sin³x=a³, secx - cosx= b³

4) c cos³x+ 3c cis x sin²x = m,
c sin³x + 3c cos²x sinx = n

5) cotx+tanx=α , secx - cosx = β