Why this constraint is crucial in a Lagrange multiplier problem?
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Consider we need to find the max. and min. values of this function $ f(x,y)=xy $ subject to the constraint $x^2-y=12$.Why it is necessary to assume that $ yleq0$?
lagrange-multiplier
edited Nov 24 at 1:27
Bernard
117k637109
asked Nov 24 at 1:19
John adams
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Consider we need to find the max. and min. values of this function $ f(x,y)=xy $ subject to the constraint $x^2-y=12$.Why it is necessary to assume that $ yleq0$?
lagrange-multiplier
edited Nov 24 at 1:27
Bernard
117k637109
asked Nov 24 at 1:19
John adams
206
Did you construct the Lagrangian and compute it's derivatives? It should be clear then.
– Mattos
Nov 24 at 1:31
@Mattos yes i did so and while i am solving, I didnot make use this assumption , but i was wondering why this assumption is stated in the question.
– John adams
Nov 24 at 3:06
After taking derivatives of the Lagrangian, you should get a condition that $y + 2x^2 = 0$...
– Mattos
Nov 25 at 7:06
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
Consider we need to find the max. and min. values of this function $ f(x,y)=xy $ subject to the constraint $x^2-y=12$.Why it is necessary to assume that $ yleq0$?
lagrange-multiplier
edited Nov 24 at 1:27
Bernard
117k637109
asked Nov 24 at 1:19
John adams
206
Consider we need to find the max. and min. values of this function $ f(x,y)=xy $ subject to the constraint $x^2-y=12$.Why it is necessary to assume that $ yleq0$?
lagrange-multiplier
lagrange-multiplier
edited Nov 24 at 1:27
Bernard
117k637109
asked Nov 24 at 1:19
John adams
206
edited Nov 24 at 1:27
Bernard
117k637109
asked Nov 24 at 1:19
John adams
206
edited Nov 24 at 1:27
Bernard
117k637109
edited Nov 24 at 1:27
Bernard
117k637109
edited Nov 24 at 1:27
Bernard
117k637109
117k637109
asked Nov 24 at 1:19
John adams
206
asked Nov 24 at 1:19
John adams
206
asked Nov 24 at 1:19
John adams
206
206
Did you construct the Lagrangian and compute it's derivatives? It should be clear then.
– Mattos
Nov 24 at 1:31
@Mattos yes i did so and while i am solving, I didnot make use this assumption , but i was wondering why this assumption is stated in the question.
– John adams
Nov 24 at 3:06
After taking derivatives of the Lagrangian, you should get a condition that $y + 2x^2 = 0$...
– Mattos
Nov 25 at 7:06
add a comment |
Did you construct the Lagrangian and compute it's derivatives? It should be clear then.
– Mattos
Nov 24 at 1:31
@Mattos yes i did so and while i am solving, I didnot make use this assumption , but i was wondering why this assumption is stated in the question.
– John adams
Nov 24 at 3:06
After taking derivatives of the Lagrangian, you should get a condition that $y + 2x^2 = 0$...
– Mattos
Nov 25 at 7:06
Did you construct the Lagrangian and compute it's derivatives? It should be clear then.
– Mattos
Nov 24 at 1:31
Did you construct the Lagrangian and compute it's derivatives? It should be clear then.
– Mattos
Nov 24 at 1:31
@Mattos yes i did so and while i am solving, I didnot make use this assumption , but i was wondering why this assumption is stated in the question.
– John adams
Nov 24 at 3:06
@Mattos yes i did so and while i am solving, I didnot make use this assumption , but i was wondering why this assumption is stated in the question.
– John adams
Nov 24 at 3:06
After taking derivatives of the Lagrangian, you should get a condition that $y + 2x^2 = 0$...
– Mattos
Nov 25 at 7:06
After taking derivatives of the Lagrangian, you should get a condition that $y + 2x^2 = 0$...
– Mattos
Nov 25 at 7:06
add a comment |
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Did you construct the Lagrangian and compute it's derivatives? It should be clear then.
– Mattos
Nov 24 at 1:31
@Mattos yes i did so and while i am solving, I didnot make use this assumption , but i was wondering why this assumption is stated in the question.
– John adams
Nov 24 at 3:06
After taking derivatives of the Lagrangian, you should get a condition that $y + 2x^2 = 0$...
– Mattos
Nov 25 at 7:06