$20+901+51$

$\frac{\cos\left(x\right)}{\sin\left(x\right)}=\frac{\cos\left(2x+1\right)}{\sin\left(2x\right)}$

$\lim_{x\to7}\left(\frac{x^3-5x+44}{x^2-x-20}\right)$

$x^2+3x+4x-2x^2-2x+5+3x^2+5x-7$

$3x^2+24x$

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

$343\cdot2401$