$\frac{1-\sin\left(x\right)}{\cos\left(x\right)}=\frac{1+\cos\left(x\right)}{\cos\left(x\right)}$

$\frac{6+12}{2}$

$\int5x^{4+2x}\left(2x^3+1\right)dx$

$\frac{d}{dx}\left(x\left(x+6\right)^2\left(7x-1\right)^3\right)$

$\sin\left(\frac{\pi}{2}+\frac{\pi}{4}\right)$

$=x+1\:\:y=2x-1$

$\frac{dy}{dx}=2xe^{-x^2}-2xy$