I believe this soln has an error.

http://img44.imageshack.us/img44/448/math28.png

Am I right?

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- Jun 4th 2010, 07:38 PMscorpion007Is this wrong? (differential operator)
I believe this soln has an error.

http://img44.imageshack.us/img44/448/math28.png

Am I right? - Jun 4th 2010, 08:47 PMDrexel28
- Jun 4th 2010, 08:54 PMscorpion007
Sorry, I didn't think it mattered, given the context. But here they are:

http://img192.imageshack.us/img192/4918/math29.png

The reason I say it's wrong is because when you distribute the x through the first term, you end up with and similarly for the second term with y.

(Also, we assume the mixed derivatives are equal) - Jun 4th 2010, 09:04 PMDrexel28
- Jun 4th 2010, 09:11 PMscorpion007
Isn't x = x(s, t) and y = y(s, t)?

Yes, this is the chain rule for partial derivs.