Question

A 10-ft ladder is leaning against a house when its base starts to slide away. by the time the base is 3 ft from the house, the base is moving at the rate of 7 ft/sec.

Answer 1

100 = x^2 + y^2
So
2 x dx/dt + 2y dy/dt =0
So
dy/dt = -x/y dx/dt
= -x/sqrt(100-x^2) * 7 At x=3