the radius of a circle is decreasing at a constant rate of .1 centimeter per second. in terms of circumference C, what is the rate of change of the area of the circle, in square centimeters per second?

Question

anonymous · Answer

yup. then mukltiply by whatever coefficents there are for your 4 numbers

anonymous · Answer

A = pi*r^2; dA/dt = 2*pi*r*dr/dt.  We know dr/dt = 0.1cm/sec.  We need to know the 'r' at which we want to determine the change in area (dA/dt) and stick that into the equation:  dA/dt = 2*pi*r*dr/dt

anonymous · Answer

wait, why do you multiply dr/dt

anonymous · Answer

seocnd statement after Area formula

anonymous · Answer

This is a related rate problem.  The dA/dt is related to the dr/dt, which is a given.

anonymous · Answer

Yes, you want dA/dt, which equals 2*pi*r*dr/dt

anonymous · Answer

so..
the anser is -.1(2pirR)

anonymous · Answer

WAIT NO