Calculus
posted by TraiShaun
A ladder 8 meters long is leaning against a wall. If the top of the ladder is slipping down at the rate of 8 meters per second, how fast is the bottom moving away from the wall when it is 7 meters from the wall?
Please give your answer in , enter it without the units.

Steve
When the ladder base is 7m from the wall, the top is √(6449) = √15 from the ground.
When the base is x meters from the wall,
x^2 + h^2 = 64
2x dx/dt + 2h dh/dt = 0
2(7)dx/dt + 2√15 (8) = 0
dx/dt = 16√15/14 = 4.43m/s
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