If there is such a thing. I need to find [itex]\partial z / \partial x[/itex] given [itex]x + y + z = \cosh xyz[/itex]. I've never seen the likes of this before and I haven't a clue where to start. Would a reasonable start be to take [itex]\partial /\partial x[/itex] of both sides? If so, it seems like I'm going to end up with an expression in terms of partial differntials.