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The radius of the cone is increasing at ...

The radius of the cone is increasing at the rate of 4 cm/se. Its height is decreasing at the rate of 3 cm/se. When its radius is 3 cm and height is 4 cm. Find the rate of change of its curved surface area.

A

`30 pi cm^(2)//sec`

B

`10 cm^(2)//sec`

C

`20pi cm^(2)//sec`

D

`22pi cm^(2)//sec`

Text Solution

Verified by Experts

The correct Answer is:
C
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KUMAR PRAKASHAN-APPLICATION OF DERIVATIVES -TEXTBOOK BASED MCQS
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  4. The rate of increase of f(x)=x^(3)-5x^(2)+5x+25 is twice the rate of i...

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  6. The rate of change of surface area of a sphere w.r.t. radius is ………..

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  7. The rate of change of volume of a cylinder w.r.t. radius whose radius ...

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  9. f(x)=2x-tan^(-1)x-log|x+sqrt(1+x^(2))| is ……….. (x in R)

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  10. If ……….., then f(x)=x^(2)-kx+20, [0,3] is strictly increasing.

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  11. f(x)=|x-1|+|x-2| is increasing if ………..

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  13. y=mx+4 touches y^(2)=8x, if m = ………..

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  14. The measure of the angle between the curves y=2 sin^(2)x and y = cos 2...

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  16. The local minimum value of x^(2)+(16)/(x)(x ne 0) is ………….

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  17. The minimum value of sec x, x in [(2pi)/(3),pi] is ……….

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  18. The maximum value of cosec x, x in [(pi)/(6), (pi)/(3)] is ………

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