$\frac{sen\left(x\right)-sen\left(y\right)}{cos\left(x\right)-cos\left(y\right)}+\frac{cos\left(x\right)+cos\left(y\right)}{sen\left(x\right)+sen\left(y\right)}$

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

$\left(\frac{1}{2x}\right)\:+\left(1.9x^2y\right)$

$\lim_{x\to\infty}\left(\left(x^3\right)\cdot5^{-x}\right)$

$g^2-9g+18$

$x^2\frac{dy}{dx}+6xy+4x^4=0$

$\lim_{x\to\infty}\left(x^{x^{-2}}\right)$