$$sin2x-2cos^2x$$

$$\int\frac{5x^2+6x+2}{x\left(x+1\right)^2}dx$$

$$.43+.6+4.1+.21$$

$$-24+3-3^2$$

$$-b+b^2$$

$$\lim_{x\to3}\left(\frac{x^2-9}{2x^2+7x+3}\right)$$

$$\sec^2\left(x\right)-\csc^2\left(x\right)=\left(\tan\left(x\right)+\cot\left(x\right)\right)^2$$