The volume of a sphere is given by
You have all the info to sub into the above derivative and solve for dr/dt.
Then, you can use that result in the surface area derivative.
Air is being pumped into a spherical balloon so that its volume increases at a rate of 80cm^3/s . How fast is the surface area of the balloon increasing when its radius is 11cm ?
... i found the derivative of Surface Area to be 8*pi*r*(dv/dt)=(ds/dt)
i keep getting 7040*pi as my answer.. but its not correct.
please help mee!