$\:y=\frac{2x}{\left(x+1\right)^2}$

$\frac{d}{dx}\:\frac{3x^2}{\sqrt{n}}+\sqrt{4x}$

$a^2+10a+15$

$\left(45-m\right)^2$

$\frac{e^xdx}{e^{-2x-y}}=\frac{ydy}{e^{-y}}$

$\lim_{x\to\infty}\left(ln\left(3x-ln\left(x+2\right)\right)\right)$

$\int9\sec^2\left(x\right)\tan\left(x\right)dx$