How does fmincon work? Why does this syntax not work?

S(1)=20; S(2)=20; S(3)=20; P(1)=20; P(2)=15; Umin=1; Umax=220; x0=[1 1 1 1 1 1 1 1]; A=[ 1 1 0 0 0 0 0 0 0 0 1 1 0 0 0 0 0 0 0 0 1 1 0 0 -1 0 -1 0 -1 0 0 0 0 -1 0 -1 0 -1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 -1 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 0 1 0 0 -1 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 -1 0 0 0 0 0 0 0 0 -1 0 0]; B=[S(1) S(2) S(3) -P(1) -P(2) Umax Umax Umin Umin S(1) S(1) S(2) S(2) S(3) S(3) 0 0 0 0 0 0 ]; [x,fval]=fmincon(@objEx61,x0,A,B)

//here is the object function function [f]=objEx61(x) ro=0.145; l(1)=3; l(2)=4; l(3)=2; l(4)=6; l(5)=3; l(6)=5; Umin=1; Umax=220; a=3.56; b=1370.2; c=106310; Cw=170; Tj=4000; Cp=4500; i(1)=(a*x(7)^2+b*x(7)+c)*l(1); i(2)=(a*x(8)^2+b*x(8)+c)*l(2); i(3)=(a*x(7)^2+b*x(7)+c)*l(3); i(4)=(a*x(8)^2+b*x(8)+c)*l(4); i(5)=(a*x(7)^2+b*x(7)+c)*l(5); i(6)=(a*x(8)^2+b*x(8)+c)*l(6); I=i(1)+i(2)+i(3)+i(4)+i(5)+i(6); W=(x(1)+x(2)+x(3)+x(4)+x(5)+x(6))*Cw*Tj; E=Cp*ro*((1/(x(7)^2)*x(1)^2*l(1))+(1/(x(8)^2)*x(2)^2*l(2))+(1/(x(7)^2)*x(3)^2*l(3))+(1/(x(8)^2)*x(4)^2*l(4))+(1/(x(7)^2)*x(5)^2*l(5))+(1/(x(8)^2)*x(6)^2*l(6)); f=I+W+E;

//this is the error Error using feval Error: File: objEx61.m Line: 25 Column: 159 Unbalanced or unexpected parenthesis or bracket.

Error in fmincon (line 601) initVals.f = feval(funfcn{3},X,varargin{:});

Error in matEx6 (line 31) [x,fval]=fmincon(@objEx61,x0,A,B) Caused by: Failure in initial user-supplied objective function evaluation. FMINCON cannot continue.

[John D'Errico]

Read the error message. You have too many or too few parens or brackets in one or more of your expressions.

Just look carefully at your code.