$\frac{\sin\left(2x\right).\csc\left(x\right)-\cot\left(x\right).\sin\left(x\right)}{\cos\left(x\right)}$

$\frac{4x^2-8x+3}{36x^3+66x^2+40}$

$1+2.08k\le19.72$

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

$\lim_{x\to\infty}\:\frac{\left(2x^6-x^4\right)}{2}$

$ab-bc+ad-cd$

$\frac{dy}{dx}=\frac{\left(1+x\right)\left(y-1\right)^2}{x^2y+x^2+4y-4}$