00:01
Okay, so the volume of a cylinder with a height h and radius r is given as pi r square h.
00:09
The problem says that assume that h and r, they vary with time, right? so for part a, all we need to find is how is the volume changing per time and just solve the problem, right? so we're gonna do, we're gonna find out what dv over dt is equal to, right? so pi is a constant in this case.
00:32
So we're gonna be using product rule over here since we have r and h, two different variables.
00:39
So we use the product rule.
00:41
Since pi is a constant, we just have pi, derivative of r square would be just 2r and then h would be there.
00:52
But also keep in mind that r is changing with time.
00:56
So we have dr over dt and then plus pi again is a constant.
01:03
We have r square, derivative of h is just 1 and then again using chain rule, h is changing with time.
01:12
So we have dr over dt...