$1-\left(m-n\right)^2$

$-ab\:;\:a=8\:y\:b=-4$

$\lim_{x\to\infty}x^2-3x+8$

$x^3+2x^2-1$

$sin\left(sin-\frac{3}{5}+cos-\frac{20}{29}\right)$

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

$\frac{3-x^2}{x^2-5}$