$\left(1-\sin^2\left(a\right)\right)\left(1+\tan^2\left(a\right)\right)$

$4xy^2+8\cdot2xy^1-xy$

$x-5^2$

$\lim_{x\to\infty}\left(\frac{\left(2^x+3^x\right)}{10^{\frac{x}{2}}}\right)$

$\left(5z^2\right)^4$

$\frac{\sin^3\left(x\right)}{\cos\left(x\right)-\cos^3\left(x\right)}$

$\frac{x^5-2x^3+9x+6}{x^2+3}$