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

$x^2+5x\:+\:121$

$\sin\left(90-x\right)=\cos\left(x\right)$

$\left(\frac{7}{2}c^2+\frac{3}{4}d^3\right)\left(\frac{7}{2}c^2-\frac{3}{4}d^3\right)$

$\left(\frac{a^2\left(f+u-k\sqrt{gx}\right)}{x^2}\right)$

$+\left(3-2\left(-17\right)\right)$

$\lim_{x\to2}\left(x^2+x-3x^3+2x^2-x+1\right)$