Chapter 6.3, Problem 1QR

To determine

To calculate: the derivative of $y=-\cos x$ .

Answer to Problem 1QR

  $\sin x$

Explanation of Solution

Given information: The function is $y=-\cos x$

Formula used: Use formula $\frac{d}{dx}\left(\cos x\right)=-\sin x$

Calculation: Differentiate $y=-\cos x$ with respect to $x$

  $\begin{array}{c}\frac{dy}{dx}=\frac{d}{dx}\left(-\cos x\right)\\ =-\frac{d}{dx}\left(\cos x\right)\\ =-\left(-\sin x\right)\\ =\sin x\end{array}$

Hence, $\frac{dy}{dx}=\sin x$