$cos\left(x\right)=\frac{2}{7}$

$2\sin\left(x\right)^2-1=\sin\left(x\right)^2-\cos\left(x\right)^2$

$\left(n+1\right)^6-\left(n+1\right)^2$

$\left(7x^2\:-\:12y^3\right)\left(7x^2\:\:+\:12y^3\right)$

$\sqrt[4]{\frac{81c^{12}b^5a^3}{144a^3b^3c^{16}}}$

$\frac{senx}{cosx}+\frac{cosx}{senx}=\frac{secx}{senx}$

$x^2-18x+90$