$3x^2\left(x^2+5x-1\right)-4x\left(2x^3-x+3\right)$

$cos^2\theta\:\left(tan^2\theta\:\:+1\right)=1$

$\left(3a^3+2\right)\left(3a^3-9\right)$

$4b^2+12bc+9c^2\left(2b+3c\right)$

$\cos^2\left(x\right)=\frac{\cot\left(x\right)^2}{\csc\left(x\right)^2}$

$\left(3x-5\right)\left(9x^2+15x+25\right)$

$3a^2+5a^3+2a^4$