How to solve the nonlinear optimization problem.

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function f = ObjectiveFunction(x)
f= x(4)
lb = [0,0,0,-Inf]
Aeq = [1 1 1 0], 
beq = 1
function [C, Ceq] = NLCon(x)
C(1)= (0.3*((1-((0.5422)^x(1))*((0.4142)^x(2))*((0.6818)^x(3)))/(1+((0.5422)^x(1))*((0.4142)^x(2))*((0.6818)^x(3))))+0.7*((1-((0.1892)^x(1))*((0.0905)^x(2))*((0.5422)^x(3)))/(1+((0.1892)^x(1))*((0.0905)^x(2))*((0.5422)^x(3)))))-x(4);
C(2)= (0.3*((1-((0.1892)^x(1))*((0.5422)^x(2))*((0.2968)^x(3)))/(1+((0.1892)^x(1))*((0.5422)^x(2))*((0.2968)^x(3))))+0.7*((1-((0.0905)^x(1))*((0.4142)^x(2))*((0.0905)^x(3)))/(1+((0.0905)^x(1))*((0.4142)^x(2))*((0.0905)^x(3)))))-x(4);
C(3)= (0.3*((1-((0.4142)^x(1))*((0.8340)^x(2))*((0.5422)^x(3)))/(1+((0.4142)^x(1))*((0.8340)^x(2))*((0.5422)^x(3))))+0.7*((1-((0.0905)^x(1))*((0.0905)^x(2))*((0.1892)^x(3)))/(1+((0.0905)^x(1))*((0.0905)^x(2))*((0.1892)^x(3)))))-x(4);
Ceq= [];
x0 = [1 1 1 30]/3
fun = @ObjectiveFunction;
Nonlcon = @NLcon;
[X, FVAL]=fmincon(fun, x0, A, b, Aeq, beq, lb, ub, Nonlcon)
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Alan Weiss 2020-6-8

I'm sorry, but I do not understand your code. Maybe you did it right, but what you wrote doesn't make sense to me. It should look like this:

lb = [0,0,0,-Inf];
Aeq = [1 1 1 0];
beq = 1;
x0 = [1 1 1 30]/3;
fun = @ObjectiveFunction;
Nonlcon = @NLcon;
A = [];
b = [];
ub = [];
[X, FVAL] = fmincon(fun, x0, A, b, Aeq, beq, lb, ub, Nonlcon)
function f = ObjectiveFunction(x)
f = x(4);
end
function [C, Ceq] = NLcon(x)
C(1)= (0.3*((1-((0.5422)^x(1))*((0.4142)^x(2))*((0.6818)^x(3)))/(1+((0.5422)^x(1))*((0.4142)^x(2))*((0.6818)^x(3))))+0.7*((1-((0.1892)^x(1))*((0.0905)^x(2))*((0.5422)^x(3)))/(1+((0.1892)^x(1))*((0.0905)^x(2))*((0.5422)^x(3)))))-x(4);
C(2)= (0.3*((1-((0.1892)^x(1))*((0.5422)^x(2))*((0.2968)^x(3)))/(1+((0.1892)^x(1))*((0.5422)^x(2))*((0.2968)^x(3))))+0.7*((1-((0.0905)^x(1))*((0.4142)^x(2))*((0.0905)^x(3)))/(1+((0.0905)^x(1))*((0.4142)^x(2))*((0.0905)^x(3)))))-x(4);
C(3)= (0.3*((1-((0.4142)^x(1))*((0.8340)^x(2))*((0.5422)^x(3)))/(1+((0.4142)^x(1))*((0.8340)^x(2))*((0.5422)^x(3))))+0.7*((1-((0.0905)^x(1))*((0.0905)^x(2))*((0.1892)^x(3)))/(1+((0.0905)^x(1))*((0.0905)^x(2))*((0.1892)^x(3)))))-x(4);
Ceq= [];
end