$$\left(2xy+x^2\right)\frac{dy}{dx}=3y^2+2xy$$

$$\lim_{x\to0}\left(\frac{sec^2x}{cosx}\right)$$

$$\frac{1-\sin}{\left(\sec-\tan\right)^2}=1+\sin$$

$$\frac{1}{cot^2x}=sec^2x-1$$

$$4+\frac{12}{4}$$

$$10x-2=6x-18$$

$$9x^2-12ab+46^2$$