2012-10-29, 12:55 AM
5x^2 + 5y^2 - λ(xy-1)
d/dx = 10x - λy
d/dy = 10y - λx
d/dλ = 1 - xy
Set all to 0 and rearrange
10x = λy
10y = λx
10x/10y = λy/λx <== This is the step where you get rid of λ, it shouldn't get a value assigned to it.
x/y = y/x
x = y
1 - x^2 = 0
x = +/- 1
y = +/- 1
And remember if x = -1, y must = -1 and if x = 1, y must = 1
d/dx = 10x - λy
d/dy = 10y - λx
d/dλ = 1 - xy
Set all to 0 and rearrange
10x = λy
10y = λx
10x/10y = λy/λx <== This is the step where you get rid of λ, it shouldn't get a value assigned to it.
x/y = y/x
x = y
1 - x^2 = 0
x = +/- 1
y = +/- 1
And remember if x = -1, y must = -1 and if x = 1, y must = 1