Question

how do you find fxy?

Answer 1

question please?

Answer 2

You mean f(x,y)?

Answer 3

no, f_xy

Answer 4

F(x,y)=x^2 +5y^2 -3xy+13y

Answer 5

Do you have to sketch a graph of it?

Answer 6

b/c it looks like you're not trying to find any specific z-value.

Answer 7

no find the max, min, or saddle point

Answer 8

take derivative with respect to x while holding y constant then take derivative of THAT derivative with respect to y while holding x constant

so

Answer 9

rlerner, look up "critical points" in your book.

Answer 10

http://tutorial.math.lamar.edu/Classes/CalcIII/RelativeExtrema.aspx

Answer 11

got it, thanks!

Answer 12

Good :-). It's good that you work through this now instead of on the exam (thumbsup)

Answer 13

hhaha :)