$\int_0^1\left(\frac{4}{1+x^2}\right)dx$

$\lim_{x\to\infty}\left(\frac{2x^{-1}\:+3x^{-2}\:}{x^2}\right)$

$\lim_{n\to\infty}\left(n-\sqrt{n+a}\sqrt{n+b}\right)$

$\cos^2\:u\:+\:4\sin\:u\:-\:4\:=\:0$

$\frac{tan\left(x\right)csc\left(x\right)}{sec\left(x\right)}=1$

$\int\left(8xe^{3x^2}\right)dx$

$67\:-\:\left(-43\right)$