$\cos^2x=\sin^2x\cos^2$

$4x^3+36x^2-4x-36$

$\int\frac{\left(3x^2-4\right)}{\left(x^2+4\right)\left(x-2\right)}dx$

$\frac{-4x^4+4x^3+7x^2+9x+3}{-7+x^2+6x}$

$\frac{tan\left(x\right)-tan\left(x\right)sin^2\left(x\right)}{cos^2\left(x\right)}$

$\frac{dy}{dx}=\frac{6+\sqrt{x}}{6+\sqrt{y}}$

$\int\left(\frac{\sqrt{x}+1}{\sqrt{x}\:-1}\right)dx$