http://calc3.askbot.com/questions/Open source question and answer forum written in Python and DjangoenCopyright Askbot, 2010-2011.Wed, 09 Jul 2014 20:54:50 -0500http://calc3.askbot.com/question/72/chain-rule/So I've just now been working on 14.4 the chain rule (late, I know). And I'm having some issues with 3 and 4. I understand the chain rule and how it works, and got 1 and 2 with no issues. My issue I'm running into now has to do with it being with respect to s and t now instead of x and y. So the problem states to use the chain rule to solve for $\frac {\partial z} { \partial s}$ and $\frac{\partial z}{\partial t}$ $$z = x^2y \quad x=\sin(st) \quad y= t^2+s^2$$ So I guess here is where I get confused. Do you replace x and y with their respective equations, then take the partial derivatives from there? Or is it some sort of combination of the original z equation plus the derivitavies of x and y separrately. The book gets the answer..$$ 2xyt\cos(st) + 2x2s, \quad 2xys\cos(st) +2x2t$$ So I'm lost, any help would be greatly appreciated! Thanks!TiffanyWed, 09 Jul 2014 20:54:50 -0500http://calc3.askbot.com/question/72/