$\int \frac{d x}{\left(e^{x}+e^{-x}\right)^{2}}=?$

$\frac{1}{2\left(e^{2 x}+1\right)}+c$

$\frac{-1}{2\left(e^{2 x}+1\right)}+c$

$\frac{1}{2 e^{2 x}}+c$

$\frac{-1}{2 e^{2 x}}+c$