A ladder rests against a vertical wall

MATHEMATICS · Subjective · A Level · Mathematics · Differentiation · Differentiation

Problem

10\text{ ft}

ladder rests against a vertical wall. The foot of the ladder slides away from the wall at

3\text{ ft}\!\big/\!\text{s}

. Find the rate at which the top of the ladder is descending when the foot is

6\text{ ft}

from the wall.