Thread: Derivative question

I'm particularly confused on this question:

Find the derivative:

tan xy - (x^3)(y) = 3sec y + 7x^2


My biggest confusion is the tan xy portion. I really don't know where to start on that. The rest I can probably figure out - product rule for the second term with dy/dx, and so on.

Thanks in advance.

d/dx tan(xy)
= sec^2(xy) *[x*dy/dx +y]