A cylindrical tank with radius 5m is being filled with water at a rate of $3m^3/min$ How fast is the height of the water increasing?
I know that $dv/dt = 3$
And that $v= \pi r^2 h$
So I want to find the derivative of h
$h= \frac {v}{ \pi r^2}$
$h' = \frac{3 \pi * 25}{ (\pi * 25)^2 }$
$h' * v'$
This gives an incorrect answer and I am not sure why.