$\lim_{x\to0}\left(\frac{5\cos\left(t\right)-5}{t^2}\right)$

$\lim_{x\to\infty}\left(\frac{4\left(1-\cos\left(x\right)-2x^2\right)}{x^2\left(1-\cos\left(x\right)\right)}\right)$

$\frac{\left(3^2+3\right)}{-6}$

$\frac{64-n^2}{8-n}$

$4x^4-40x^2+36$

$\frac{\left(x+8\right)}{2x^2-13x-7}$

$\cos\left(y\right)\sec\left(y\right)=1$