$\int\sec\left(7x\right)\cos\left(7x\right)dx$

$7^2-3^2\cdot4$

$-10\left(9+3n\right)+3\left(5+n\right)$

$2x+1\:+\:2x-1\:area$

$\frac{\cos\left(a\right)}{\sin\left(a\right)}-\frac{\sin\left(a\right)}{\cos\left(a\right)}$

$8m^6-27$

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