- #1
Yankel
- 395
- 0
Hello all
I am trying to find minimum and maximum of the following function:
\[f(x,y)=4x^{2}-y^{2}-xy-2x+6y\]
under the constraints:
\[y=4-2x\]
\[x\geq 0\]
\[y\geq -2\]I tried solving this problem using the method of the method of bounded and closed domain, understanding that the constraints creates a triangle. I checked every line in the triangle, the edge points and the local min and max for each line (if there were any).
I got that the minimum value was f(0,-2)=-16 and the maximum was f(3,-2)=20
(should I have used Lagrange multipliers ?)
The problem is:
1. I entered this problem to MAPLE, and got max like mine, but min at f(0.5,3)=7.5. I found this point, but it isn't the absolute minimum.
2. In the answers sheet for this problem there are 4 possible answers for the sum of the min+max: 30.5, -7, 0. 16.
Non of them are according to my solution or MAPLE's.
Can you please assist me with solving this problem ?
Thank you !
I am trying to find minimum and maximum of the following function:
\[f(x,y)=4x^{2}-y^{2}-xy-2x+6y\]
under the constraints:
\[y=4-2x\]
\[x\geq 0\]
\[y\geq -2\]I tried solving this problem using the method of the method of bounded and closed domain, understanding that the constraints creates a triangle. I checked every line in the triangle, the edge points and the local min and max for each line (if there were any).
I got that the minimum value was f(0,-2)=-16 and the maximum was f(3,-2)=20
(should I have used Lagrange multipliers ?)
The problem is:
1. I entered this problem to MAPLE, and got max like mine, but min at f(0.5,3)=7.5. I found this point, but it isn't the absolute minimum.
2. In the answers sheet for this problem there are 4 possible answers for the sum of the min+max: 30.5, -7, 0. 16.
Non of them are according to my solution or MAPLE's.
Can you please assist me with solving this problem ?
Thank you !