posted by chris .
a 20m ladder rests vertically against the side of a barn. a pig that has been hitched to the ladder starts to pull the base of the ladder away from the wall at a constant rate of 40 cm per second. find the rate of change of the height of the top of the ladder after 30 secs
Using Pythagorean theorm,
where b is the base length, and h is the height.
Taking the derivative..
0=2b db/dt + 2h dh/dt
you are given db/dt, solve for dh/dt
For the second part, you will have to find b and h at 30 sec. b will be .40*30, solve for h, and again, you have it.