$\tan\left(\frac{x}{2}\right)+\cot\left(x\right)-1=0$

$\left(1-x\right)\left(-3-x\right)$

$\frac{d^2}{dx^2}\left(-\frac{1}{2}x^4-\frac{4}{5}x^5+\frac{1}{3}\right)$

$\int sen\left(\frac{\pi\:}{3}-x\right)dx$

$121-16z^4$

$\frac{cos2x+sin2x}{1+tan2x}$

$\int6x\sin\left(5x\right)dx$