Ripple Spread. A stone is thrown into a pond, creating a circular ripple that spreads over...

Ripple Spread. A stone is thrown into a pond, creating a circular ripple that spreads over the pond in such a way that the radius is increasing at a rate of 3 ft / sec.

a) Find a function r(t) for the radius in terms of t.

b) Find a function A(r) for the area of the ripple in terms of the radius r.

c) Find (A ° r)(t). Explain the meaning of this function.