$13-4x=1-x$

$\frac{\left(4x^4-4x^3+6x^2-4x+5\right)}{\left(x^3-2\right)}$

$cos2\left(\frac{3}{\sqrt{13}}\right)$

$63y-43y^3-76y^2+25y+y^3$

$\frac{d^6}{dx^6}\sin\left(4x\right)$

$\lim_{x\to0}\left(\frac{3x^2+\tan^2\left(2x\right)}{\sin^2\left(4x\right)}\right)$

$5+x^3\cdot x^3$