$\frac{\frac{1}{cos\left(x\right)}-cos\left(x\right)}{sin\left(x\right)}$

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

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

$\sqrt{7^4}$

$\left(7x^6-5\right)\left(7x^6+3\right)$

$\lim_{x\to\infty}\left(\frac{x^2}{csc\left(\frac{1}{3x^2}\right)}\right)$

$2\sqrt{25a}-2\sqrt{9a}+3\sqrt{4a}$