## University Calculus: Early Transcendentals (3rd Edition)

$\frac{dy}{dx}=(-2e^{\frac{-x}{5}})$
$y=10e^{\frac{-x}{5}}$ on differentiating both sides: $\frac{dy}{dx}=\frac{d(10e^{\frac{-x}{5}})}{dx}$ $\frac{dy}{dx}=(10\frac{-1}{5}e^{\frac{-x}{5}})$ $\frac{dy}{dx}=(-2e^{\frac{-x}{5}})$