Partial diffrentiation not working

This is the following code has an error as :

"  Error using sym/diff (line 69)
The second argument must be a variable or a nonnegative integer specifying the number of differentiations.

Error in quiz21 (line 36)
    J(j,1)=diff(g,var(j));         % partial derivative matrix
"

The code is given below :

function var1= quiz21()

syms x1 x2 x3 x4 lm
var=[ x1 x2 x3 x4 ]'; % variables matrix , showing number of variables

f(1,1) = (x4)^3 - (204 +2.4*x2 + 0.02*x2*x1 - 1.5*x1) ;  % governing equation

f(2,1) = x3 - 1.2*(x4)^2 ;                                % 3 constraint equations f(2,1), f(3,1) ,f(4,1)
f(3,1) = x4 - ( -5 - x2 )*10*( 1 - exp(-7.621/10)) ;
f(4,1) = x3 - ( x1 - 30 )*19.2*( 1 - exp(-13.31/19.2)) ;

numeq=length(f); % f1+f2+f3+f4

J = sym('A',[numeq 1]); % Column matrix J
p = 10;

g= (f(1,1)- p*( f(2,1) + f(3,1) + f(4,1)));   % new equation;  containing g.e. + constraints with 'p' weight.

disp(g);

for j=1:numeq  % rows of J 

      J(j,1)=diff(g,var(j));         % partial derivative matrix

end 

disp(J)

Answer 1

[Walter Roberson]

You have

   var=[ x1 x2 x3 x4 ]';

But' is conjugate transpose. You need .' instead of '

[madhan ravi]

+1 useful