Question

matlab中二元函数有约束求极值的问题

函数是P=(x-2)*(-0.5133*x+5.042)*(-0.0426*y.^2+0.4092*y+1.0187)-y
约束条件是
2≤x≤9.8
0≤y≤7
要怎么求得极值啊？
有个地方错了 P=10^(-4)*(x-2)*(-0.5133*x+5.042)*(-0.0426*y.^2+0.4092*y+1.0187)-y

求极大值

Answer 1

>> P=@(x)(x(1)-2)*(-0.5133*x(1)+5.042)*(-0.0426*x(2).^2+0.4092*x(2)+1.0187)-x(2);
lb=[2;0];ub=[9.8;7];x0=[1;1];[x,fval]=fmincon(P,x0,[],[],[],[],lb,ub)

Local minimum found that satisfies the constraints.

Optimization completed because the objective function is non-decreasing in
feasible directions, to within the default value of the function tolerance,
and constraints are satisfied to within the default value of the constraint tolerance.

<stopping criteria details>

x =

2.0000
7.0000

fval =

-7.0000
上述说明：当x=2,y=7时有极小值p=-7