### Home > APCALC > Chapter 9 > Lesson 9.1.3 > Problem9-40

9-40.

No calculator! A point is moving along the graph of $y = \cos(x)$ so that $\frac { d x } { d t }= 3$ . Determine the rate at which $y$ is changing when $x =\frac { \pi } { 4 }$. Homework Help ✎

$\frac{dy}{dt}=\frac{dy}{dx}\cdot \frac{dx}{dt}$