$\frac{\sen^{2}\theta-\cos^{2}\theta}{1-\sin^{2}\theta}$

$\lim_{x\to infinity}\left(\left(1+\frac{4}{x}\right)^{\frac{x}{11}}\right)$

$\frac{8^{-\frac{1}{3}}z^{-\frac{2}{5}}}{w^{-5}z^{\frac{3}{5}}}$

$v^2-18v$

$\frac{x^2-19x+5}{\left(x+1\right)\left(x^2+4\right)^2}$

$i ( 2 + i )$

$\left(\frac{y^{12}}{y^4}\right)^3$