$\cos\:^4\left(a\right)+\left(1-\cos\:^2\left(a\right)\right)\cos\:^2\left(a\right)$

$\int\frac{5x+8}{x^2-5x+6}dx$

$21d+28d$

$4w^6x^2-24w^3xyz+36y^2z^2$

$\lim_{x\to\infty}\left(\frac{x^2+9x-5}{4-x^3}\right)$

$\frac{1}{3}xy-\frac{4}{5}xy$

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