SOLUTION: 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

Algebra ->  Trigonometry-basics -> SOLUTION: 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      Log On


   

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.
Answer by ikleyn(52832) About Me  (Show Source):
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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.
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  the area  of a circle is  A = pi%2Ar%5E2.


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


           %28dA%29%2F%28dt%29 = 2%2Api%2Ar%2A%28%28dr%29%2F%28dt%29%29 = 2%2Api%2A6%2A2 = 24pi = 24%2A3.14 = 75.36  cm^2 per minute  (rounded).    ANSWER



  (b)  Solve  it by the same way as (a)

Solved.