The radius, r cm , of a spherical balloon at a time t seconds is given by

r = 3 + 2 / (1+t)

What is the initial radius? Find the rate of change of r (w.r.t.t) when t=3

1 answer

I'll do one, just for grins.

if you're taking calculus, you should surely be able to do

r = 3+2/(1+0)

to get the radius when t=0!

Having mastered the arcane art of plugging in a value, and knowing that

dr/dt = -2/(1+t)^2

you can probably figure what dr/dt is when t=3.