A circle is shrinking so that its radius decreases at

MATHEMATICS · Subjective · AP · Calculus AB · Contextual Applications of Differentiation · Contextual Applications of Differentiation

Problem

0.2\,\text{cm/s}

. When the radius is

10\,\text{cm}

, what is the sign of

\dfrac{dA}{dt}

? Give a brief reason for your answer.