Posted by **chris** on Monday, December 8, 2008 at 4:10pm.

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

- calculus helpppp! -
**bobpursley**, Monday, December 8, 2008 at 4:40pm
Using Pythagorean theorm,

length^2=b^2+ h^2

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.

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