I don't really know how to do implicit differentiation. Could you show me how to do it with the equation y-sin(xy)=x ² ? Thanks!
I assume the main trouble is to get $\displaystyle \frac{d \sin (xy) }{dx}$ (if it isn't then I suggest you go back and review the topic and then attempt some easier questions). First make the substitution $\displaystyle u = xy$ and use the chain rule:
$\displaystyle \frac{d \sin (xy) }{dx} = \frac{d \sin u}{du} \cdot \frac{du}{dx} = \cos u \cdot \frac{du}{dx} = \cos (xy) \cdot \frac{d (xy)}{dx}$.
I assume you can use the product rule to get $\displaystyle \frac{d (xy)}{dx} = y + x \frac{dy}{dx}$ and then put it all together.