Question

____ $y=\frac{1}{1 + x}$

Explanation:

Step1: Recall antiderivative rule

The antiderivative of $\frac{1}{1 + x}$ is $\ln(1 + x)+C$ (where $C$ is the constant of integration) because the derivative of $\ln(u)$ with respect to $x$ is $\frac{u'}{u}$, and when $u = 1 + x$, $u'=1$.

Answer:

$y=\ln(1 + x)+C$