$\int x^2\frac{1}{\sqrt{x^2-9}}dx$

$7+x-5x^2-4x+9x^2-8x\:\:+\:x+3xy+2y-11x-xy+9$

$\frac{x^2y^{-7}}{x^8y^{-5}}$

$4x^5-36x$

$\frac{cos\:\left(4x\right)-cos\left(2x\right)}{sen\:\left(2x\right)-sen\:\left(4x\right)}$

$\left(\frac{\cos\left(x\right).\sec\left(x\right)}{\csc\left(x\right)}\right)\left(2\sin\left(x\right)\right)$

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