$\int\tan^5x\sin^2xdx$

$\frac{d\left[u\right]}{dt}=-k\left[u\right]$

$\lim_{x\to\infty}15e^{\frac{1}{x}}-15x$

$\frac{dr}{d\theta\:}\:=\left(r+e^{-\theta\:}\right)tan\:\left(\theta\:\right)$

$\frac{y^8-9}{y^4+3}$

$\lim_{x\to\infty}\left(\frac{e^x-1}{3x^2+4}\right)$

$8yb+3a+8ya+3b$