$\left(x^{\frac{2}{3}}\right)^{\frac{1}{4}}$

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

$\sin\left(-\pi\right)+\cos\left(-\pi\right)$

$\left(-5x+19\right)^2$

$\left(-6a-1\right)^2$

$\frac{1^3-1}{1^2}$

$\int\cos\left(\frac{x}{2}\right)\cdot\cos\left(nx\right)dx$