1. ## hard differential

Can anyone differentiate this?
$cos(ytan(x))=ln(xy)$ The answer is $\frac{(1+2cos(y)\frac{dy}{dx})(x-y)-(x+2sin(y)+4)(1-\frac{dy}{dx})}{(x-y)^2}=-cosec^2(y)\frac{dy}{dx}$ thanks id love to know like the stages before this!! My bad this was a mistake,,i know the answer sorry,,,read the wrong answer,,,i may posty another q here tho,,,,,''. ina few minutesXD

2. did you leave out a close parenthesis ? ...

$\cos(y \cdot \tan(x)) = \ln(xy)$

or

$\cos(y) \cdot \tan(x) = \ln(xy)$

?