Question

find $\frac{d^{2}}{dx^{2}}(sin x+cos x)$. $\frac{d^{2}}{dx^{2}}(sin x+cos x)=square$

Explanation:

Step1: Find first - order derivative

The derivative of $\sin x$ is $\cos x$ and the derivative of $\cos x$ is $-\sin x$. So, $\frac{d}{dx}(\sin x+\cos x)=\cos x - \sin x$.

Step2: Find second - order derivative

Differentiate $\cos x-\sin x$ with respect to $x$. The derivative of $\cos x$ is $-\sin x$ and the derivative of $-\sin x$ is $-\cos x$. So, $\frac{d^{2}}{dx^{2}}(\sin x+\cos x)=-\sin x-\cos x$.

Answer:

$-\sin x - \cos x$