$\frac{1+\frac{\sin\left(x\right)}{\cos\left(x\right)}}{1-\frac{\sin\left(x\right)}{\cos\left(x\right)}}$

$x^6-4x^3+3$

$2t+4>50$

$\int\left(6x\left(2x^2+9\right)^{\frac{1}{2}}\right)dx$

$-4+3\ge15$

$\left(x^2\:-\:2x\:\right)^2$

$\lim_{y\to4}\frac{\left(3-y\right)}{y^2-2y-8}$