- #1
toothpaste666
- 516
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Homework Statement
I need to find the absolute extrema of the function in the specified region
f(x, y) = x^2 + xy R = {(x,y): |x|<=2, |y|<=1}
The Attempt at a Solution
The first partial derivatives are
fx(x,y) = 2x+y and fy(x,y) = x
They are both 0 only when x and y are both 0. So (0,0) is a critical point and f(0,0) = 0 now we look at the boundaries:
f(2,1) = 4 +2 = 6
f(2,-1) = 4-2 = 2
f(-2,1) = 4-2 = 2
f(-2,-1) = 4+2 = 6
so the absolute min is at (0,0) (this would normally be a saddle point but in the specified region it is a minimum) and the absolute max are at (2,1) and (-2,-1)
Am I correct about this?