$\frac{\cos\left(x\right)}{\cot\left(x\right)}+\tan\left(x\right)\:\left(\cos\:\left(x\right)\right)\:$

$\frac{5}{6}\:x\:\frac{7}{9}$

$1-20x^2+100x^4$

$\ln\left(y-3\right)-\ln\left(9\right)=x+\ln\left(x\right)$

$\frac{\left(4x^3+14x-5-9x^2\right)}{\left(4x-1\right)}$

$\frac{dx}{dt}=-3\cdot t^2\cdot x$

$\int\left(20\tan^3\left(x\right)\right)dx$