use the chain and product rule on [LaTeX ERROR: Convert failed]
note [LaTeX ERROR: Convert failed]
so [LaTeX ERROR: Convert failed]
can you finish this off ?
Bobak
use implicit differentiation. note that you will need the product rule when differentiating xy. whenever you differentiate a y-term, attach y' to it (y' is another notation that means dy/dx in this context). try it (of course, you should also be aware that you are going to differentiate sin(xy) using the chain rule)
EDIT: Oh well, bobak beat me to it. and with a more specific answer