$\lim_{x\to0}\left(\frac{1-\cos\left(x\right)}{\left(e^2-1\right)^2}\right)$

$\frac{3x^2}{1+x^4}$

$\int_1^{\infty}\left(\frac{1}{x\left(x^2+5\right)}\right)dx$

$\lim_{x\to0}\left(\sqrt{1+\frac{2}{x}}-\sqrt{1+\frac{3}{x}}\right)$

$\int\:\frac{3x^2-x}{\left(x+1\right)\left(x-1\right)^2}dx$

$\int\sin\left(7\cdot x+1\right)$