The radius of a right circular cylinder is increasing at the rate of 7 in./sec, while the height is decreasing at the rate of 6 in./sec. At what rate is the volume of the cylinder changing when the radius is 20 in. and the height is 16 in.

Step-by-step explanation:

Given:

Rate of change of radius of cylinder:

(This is increasing rate so positive)

Rate of change of height of cylinder:

(This is decreasing rate so negative)

To find:

Rate of change of volume when r = 20 inches and h = 16 inches.

Solution:

First of all, let us have a look at the formula for Volume:

Differentiating it w.r.to 't':

Let us have a look at the formula:

Applying the two formula for the above differentiation:

Now, putting the values:

So, the answer is:

2 x^2 -3x+p

sum of roots = 3/2

let other root be x

3+ x = 3/2

x= 3/2 - 3 = -3/2

product of roots = p/2

3× -3/2 = p/2

-9 = p

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