A stone is dropped into a quiet lake and waves move in circles at the speed of

MATHEMATICS · Subjective · CBSE · Mathematics · Applications of Derivatives · Applications of Derivatives

Problem

5. A stone is dropped into a quiet lake and waves move in circles at the speed of

5 \mathrm{~cm} / \mathrm{s}

. At the instant when the radius of the circular wave is 8 cm , how fast is the enclosed area increasing?