Thread: Maxima proof

Hello!
I have a question I'm struggling with, my last question was answered so helpfully I thought I'd try my others out here! Especially since my exam is in less than 3 hours!

Its a 'Two variable function Extrema' question

Q: The gravitational attraction at the point (x,y)=(1/x)+(4/y)+(9/(4-x-y))
Prove that G(x,y) has a maximum value of 9

These type of questions always stump me, sorry.

Thanks for any aid

I can see why it stumped you. First, how did the exam go? Second, this function has no maximum (or minimum), local or absolute.



Consider: and because of the term.

For traditional proof, has no solution.