Error with code?

function [ C ] = Q3( x )
%   let x1 denote t
%   let x2 denote q
C = 13.9 + (58.056*((x(1)).^-0.3017)) + ((11.2657*((x(1)).^0.4925)/((x(2)).*1)) + ((0.4491*((x(1))^0.7952)/((x(2))) + ((0.06719*(2*((x(1))) + 1.2*(x(2))).^0.861)/(x(2))))+0.0450*(2*(x(1))) + 1.2*(x(2))) + 14.002*((x(2)).^-0.1899)+ 0.0002914*(((x(2)).^0.671);  

is there an error with the code? Pls answer and correct it for me. This is my m-file for using fminsearch, but I kept on getting these errors

Error: File: Q3.m Line: 4 Column: 258
Invalid expression. When calling a function or indexing a variable, use parentheses. Otherwise, check for mismatched delimiters.

Error in fminsearch (line 200)
fv(:,1) = funfcn(x,varargin{:});
 

[Torsten]

Your parentheses in the expression to define C don't match.

Answer 1

[madhan ravi]

Always break long equation to pieces:

C = 13.9 + 58.056*(x(1).^-0.3017) + ...
    (11.2657*(x(1).^(0.4925)))/(x(2).*1) + ...
    0.4491*x(1)^(0.7952)/x(2) +...
    0.06719*2*x(1) + ...
    (1.2*(x(2).^0.861))/(x(2))+0.0450*2*x(1) +...
    1.2*x(2) + 14.002*x(2).^(-0.1899)+ 0.0002914*x(2).^(0.671);  

Answer 2

[KSSV]

YOu for got to add one bracket.Check the below lines.....the braces are added properly.

C = 13.9 + (58.056*((x(1)).^-0.3017)) + .......
    ((11.2657*((x(1)).^0.4925)/((x(2)).*1))) + ......
    ((0.4491*((x(1))^0.7952)/((x(2))) + .......
    ((0.06719*(2*((x(1))) + 1.2*(x(2))).^0.861)/(x(2))))+.......
    0.0450*(2*(x(1))) + 1.2*(x(2))) +......
    14.002*((x(2)).^-0.1899)+ 0.0002914*(((x(2)).^0.671));  

[MOHAMED NOORUL ASRAR]

C = 13.9 + (58.056*((x(1)).^-0.3017)) + ((11.2657*((x(1)).^0.4925)/((x(2)).*1))) + ((0.4491*((x(1))^0.7952)/((x(2))) + ((0.06719*(2*((x(1))) + 1.2*(x(2))).^0.861)/(x(2))))+(0.0450*(2*(x(1))) + 1.2*(x(2))))/(x(2)))) + 14.006*((x(2)).^-0.1899)+ 0.0002914*(((x(2)).^0.671));

I edited the part with 0.0450 again. by dividing by x2 and then, it doesnt work now. Can you help me check?

Thanks.

Answer 3

[Zohaib Ikram]

x=linspace(0,2,10);

y=linspace(0,2,10);

z=linspace(0,2,10);

[XX,YY,ZZ]=meshgrid(x,y,z);

Q=1.e-9;

C=9.e9;

r=(x.^2+y.^2+z.^2).^.5;

Ex=Q*C/r.^3*x;

Ey=Q*C/r.^3*y;

Ez=Q*C/r.^3*z;

figure()

quiver3(x,y,z,Ex,Ey,Ez)

view(-35,45)

i found an error when i run this code any one help please ???