$\lim_{x\to0}\left(\frac{4\left(x\ln\left(1+x\right)\right)}{x\ln\left(1+x\right)}\right)$

$\frac{dy}{dx}=\frac{1+x}{xy^{17}},\:y\left(1\right)=5$

$x^3=-216$

$\frac{df}{dx}=2.1x$

$\frac{1}{\left(x^2+1\right)\left(3x^2+x^3\right)}$

$20-\frac{200}{q+20}$

$\frac{d^2}{dx^2}\left(-15\cos\left(x\right)\right)$