$\frac{d^4}{dy^4}\left(3xe^{3x}\right)$

$\tan\left(x\right)\:\:\left(1+\frac{\cos\left(x\right)^2}{\sin\left(x\right)^2}\right)=\frac{1}{\sin\left(x\right)\cdot\cos\left(x\right)}$

$4y^2\:-40yz\:+100yz^2$

$y=\sqrt[2]{x}+\frac{1}{\sqrt[3]{x}}$

$x^2-x=12$

$\left(6^2+1\right)\left(6^4+1\right)\left(6^8+1\right)$

$a^4+2a^2+1$