$f ( x ) = x ^ { 2 } + \frac { 1 } { x ^ { 2 } }$

$\lim_{x\to2}\left(\frac{2x^3-8x}{x+2}\right)$

$\frac{sen2x+cos2xsen2x}{sen2xsen2x}$

$\lim_{x\to0}\left(\frac{\sin\:\left(2x\right)^4}{4x^4}\right)$

$\frac{2x^2+5x-4}{x+3}$

$\frac{dy}{dx}=5xe^y,\:y\left(0\right)=0$

$\log\left(1+x\right)=0$