$\frac{g^2-g-6}{g^2+g-12}$

$\left(-3\right)^2-4$

$\cos x+3=2-cos\:x$

$\lim_{x\to0}\left(\frac{\cot\left(z\right)}{z^2}\right)$

$1+\cos\left(x\right)^2=1$

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

$\frac{\cos\left(t\right)\cot\left(t\right)}{1-\sin\left(t\right)}-1$