A 10-ft ladder leans against a vertical wall

MATHEMATICS · Single correct · A Level · Mathematics · Differentiation · Differentiation

Problem

A 10-ft ladder leans against a vertical wall. When the foot of the ladder is 6 ft from the wall and sliding away at 2 ft/s, what is the instantaneous rate of change of the height of the top of the ladder? (a) −0.75 ft/s-0.75\text{ ft/s} (b) +1.5 ft/s+1.5\text{ ft/s} (c) −1.5 ft/s-1.5\text{ ft/s} (d) −2.67 ft/s-2.67\text{ ft/s}

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