Question 1186787
.
The radius r of a circle is increasing at a rate of 2 centimeters per minute.

(a) Find the rate of change of the area when r = 6 centimeters.


(b) Find the rate of change of the area when r = 34 centimeters.
~~~~~~~~~~~~~~~



<pre>
  the area  of a circle is  A = {{{pi*r^2}}}.


  (a)  the rate of change the area of the circle is


           {{{(dA)/(dt)}}} = {{{2*pi*r*((dr)/(dt))}}} = {{{2*pi*6*2}}} = {{{24pi}}} = {{{24*3.14}}} = 75.36  cm^2 per minute  (rounded).    <U>ANSWER</U>



  (b)  Solve  it by the same way as (a)
</pre>

Solved.