oil from a leaking oil tanker radiates outward in the form of a circular film on the surface of the water. If the radius of the circle increases at the rate of 3 meters per min, how fast is the area of the circle increasing when the radius is 200 meters ?

π x r^2= area of circle

therefore π x200^2=125663.71

125663.71x3 = 376991.12

according to the book the answear is wrong as they have 1200π m^2/min

they did not show any working !

also

differencite this

F(x) = √ (x-1)/(x+1)

an simplify!

cheers !