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

$\int\left(3\csc\left(x\right)\cot\left(x\right)\right)dx$

$2x^2+4xy+6xz$

$\frac{\left(x+1\right)^n}{\left(2n+1\right)^2\cdot2^{3n}}$

$5x-12\le3x-4$

$\int\frac{3x-1}{\left(x+2\right)\left(x-4\right)}dx$

$\frac{dx}{dt}=-2$