Find the limit of $\sin\left(x\right)\ln\left(x\right)$ as $x$ approaches 0

Find the derivative

$\frac{d}{dx}\left(x^2+y^2\right)$

Find the derivative

$\frac{d}{dx}\left(x-2^{4x}\right)$

$\frac{d}{dx}\left(\arctan\left(x-\sqrt{1+x^2}\right)\right)$

$\frac{d}{dx}\arctan\left(x-\sqrt{1+x^2}\right)$

$\frac{d}{dx}\arccos\left(\sqrt{1-x^2}\right)$

Find the derivative

$\frac{d}{dx}\left(x\sinh x-\cosh x\right)$

$\frac{d}{dx}\left(\mathrm{sech}\left(-4x\right)\left(1-\ln\left(\mathrm{sech}\left(-4x\right)\right)\right)\right)$