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

$\left(5x\right)^{-1}$

$\int\frac{4}{x\left(x-1\right)\left(x+2\right)}dx$

$81-64w^2$

$\int_0^{\frac{\pi}{2}}\left(\frac{1}{1+4x^2}\right)dx$

$1+2q+q^2$

$\frac{\left(x-1\right)\left(1-2\right)}{\left(x+1\right)\left(x+2\right)}$