A man standing on a wharf is hauling in a rope attached to a boat, at the rate of 4 ft/sec. if his hands are 9 ft. above the point of attachment, what is the rate at which the boat is approaching the wharf when it is 12 ft away?
1 Answer
Jan 22, 2018
Explanation:
We are told:
We need to find
Pythagoras gives us the value of r at that particular instant:
We know that:
Differentiating implicitely with respect to t:
Putting in the numbers