$$\frac{\csc\theta}{\tan\theta+\cot\theta}$$

$$-134\left(-412\right)$$

$$\lim_{x\to1}\left(\frac{x^3+2x^2-x+2}{x^3-7x+6}\right)$$

$$\left(\lim_{x\to0}\left(e^x+x\right)^{\frac{1}{x}}\right)$$

$$x^2+18x-4$$

$$\int-\frac{5}{8t\sqrt{64t^2-81}}dt$$

$$\left(xy+y^2+x^2\right)dx=x^2dy$$