Friday, 24 February 2023

COMPACT REVISION (RATE MEASURE)

1) A point moves on the parabola 3y = x² in such a way that, when x= 6. The abscissa is increasing at the rate of 3 cm/second. At what rate is the ordinate increasing at the point ?                  The ordinate increases at the rate of 12 cm/sec at that point.

2) if in the rectilinear motion of a particle s= at + 1/2  ft², when u and f are constants, then prove that velocity at time t is u + ft and acceleration is f.

3) Find the co-ordinates of the position of a particle moving along the paraboz y²= 4x at which the rate of increase of the abscissa is twice the rate of increase of the ordinate.                          (4,4)

4) Show that x/(1+ x) < log(1+ x) < x, when x> 0.

5) If f(x)= (x -1) eˣ +1, show that f(x) is positive for all positive values of x.   

5) The time rate of change of radius of a sphere is 1/2π. When its radius is 5cm. Find the rate of change of the area of the surface of the sphere with time.      20cm²

6) Given y=(a sinx + b cosx)/(c sinx + d cosx),  prove that 
A) if a=1, b= 2, c= 3, d=4 then y decreases for all the value of x.
B) if a=2, b=1, c=3, d=4, then y increases for all values of x.       

7) Find the range of value of x for which
A) the function x³ -9x²+ 24x - 16 increases as x increases.   x<2 or x >4
B) the function 2x³ -9x²+ 12x - 3 decreases as x increases.          1< x < 2

8) A man 1.5 m tall walks away from a lampost 4.5 m at the rate of 4 km/hr.
A) how fast is shadow lenthening ?
B) how fast is the farther end of his shadow moving on the pavement ?

9) Water is poured into vertex into an inverted conical vessel of which the radius of the base is 2m and height 4 m at the rate of 77 litre/min . At what rate is the water-level rising at the instant when the depth is 70 cm ?       20cm/min

10) A spherical ice-ball is melting, the radius is decreasing at a constant rate of 0.1 cm per second. Find the amount of water formed in one second when the radius of the sphere is 7 cm. (Given π=22/7) sp. gr. of ice = 0.9).    55.44gm

11) the radius of a balloon is 7 cm. If an error of 0.1 cm is made as measuring the radius. Find the error in measuring the volume of the balloon.      6.16c.c

12) A spherical balloon is being inflated so that its volume increases uniformly at the rate of 40 cm³)min. How fast is its surface area increasing when the radius is 8 cm ? Find approximately, how much the radius will increase during the next 1/2 minute.                      0.025. 0.025

13) Water is pumped out at a constant rate of 88 cubic metre per minute from a conical container held with its axis vertical. If the semivertical of this cone is 45°, find  the rate of depression of the water level when the depth of the water level is 2 m.                      7 m/min

13) find the set of all values 'a' for which the function f(x)= [{√(a+4)/(1- a)} -1] x⁵- 3x + log 5 decreases for all real x.

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