$\frac{d^{26}}{dx^{26}}\cos\left(x\right)$

$25-\left(-6\right)^2$

$\int x^{-\frac{1}{2}}e^{-\sqrt{x}}dx$

$\frac{2x^2+7x+3}{x-2}$

$\left(5x-1\right)\left(5x+1\right)$

$\lim_{x\to\infty}\left(1-\frac{5}{2x}\right)^{4x}$

$\frac{\sin\left(10x\right)}{\sin\left(9x\right)+\sin\left(x\right)}$