$\cos\left(a\right)^4-\sin\left(a\right)^4=\cos\left(a\right)^2-\sin\left(a\right)^2$

$\int6^{x+3}dx$

$\lim_{x\to\frac{\pi}{2}}\left(\frac{tan\left(18x\right)}{tan\left(21x\right)}\right)$

$\frac{cos\:2x}{2\:sin\:2x\:+cos\:2x}=\frac{1}{2tan2t\:+1}$

$f\left(x\right)=\frac{-2}{\sqrt{x}}+\frac{\sqrt[5]{x}}{3}$

$\left(6^{x^2}\:^{y^3}+1\right)$

$12\cdot\left[40+\left(-3\right)\right]$