00:01
Hi, in this problem we are given maximize f of xy equal to 10 x minus 2x squared minus x cube plus 8y minus y square such that x plus y is less than equal to 2 and x comma y greater than equal to 0.
00:19
Now we are required to show that x0 y0 equal to 1 1 is not an optimal solution.
00:25
So further, the lagrangian function for this can be written.
00:30
Written as l equal to 10x minus 2x squared minus x squared minus x cubed plus 8y minus y square minus 5 of x plus y minus 2.
00:49
Consider this as equation number 1.
00:52
Now the kkt conditions are a, 5 greater than equal to 0.
00:57
Consider this as equation number 2, b, del l, by del x equal to 0, which implies that 10 minus 4x minus 3 x squared minus 5 is equal to 0.
01:09
Consider this as equation number 3 and del l by del y equal to 0, which implies that 8 minus 2y minus 5 equal to 0.
01:19
Consider this as equation number 4.
01:22
See, 5 of x plus y minus 2 equal to 0.
01:26
Consider this as equation number 5 and d x plus y minus 2 less than equal to 0 consider this as equation number 6.
01:35
Now let us take case 1 where 5 is not equal to 0 so therefore this implies that from equation 3 and 4 we can write 10 minus 4x minus 3x square equal to 8 minus 2 y.
01:59
Further, this implies that 3x square plus 4x minus 2y is equal to 2.
02:08
Consider this as equation number 7.
02:11
Now further, from the equation 5, let us consider the case x plus y minus 2 equal to 0...