$\frac{sen\left(x\right)+\csc\left(x\right)}{sen\left(x\right)}=1-\frac{1}{tan\left(x\right)}$

$\lim_{x\to\infty}\:4x\left(\sqrt{x}-\sqrt{x-1}\right)$

$2x\:-\:1\:>\:4$

$\frac{\sin\left(4x\right)}{\sin\left(2x\right)}\cdot\sec\left(2x\right)$

$m^2x+mx^2y+mx$

$\left(-2x^3y^5z^3\right)^2$

$\frac{x^3-2x^2+x+1}{x-1}$