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Problem with Argument and fsolve

Asked by satendra kumar on 29 Apr 2013
Hi everyone, I am trying to solve:
S= (50625*(arg(x*i + y - 1393 - 746*i) - 3560289735917593/36028797018963968)^2)/pi^2 + ((x + (y - 987)^2 - 24025)^(1/2)/2 - 8643/20)^2 + (3240000*(arg(x*i + y - 259 - 1571*i) + 8955599335723659/288230376151711744)^2)/(169*pi^2) + (90000*(arg(x*i + y - 375 - 629*i) - 3959779706285659/144115188075855872)^2)/pi^2
end
with fsolve. But i am getting following error message:
'Undefined function 'arg' for input arguments of type 'double'.
Error in myfun (line 2)
F = [((x(1) + (x(2) - 987)^2 - 24025)^(1/2)/2 - 8643/20)/(2*(x(1) + (x(2) - 987)^2 - 24025)^(1/2)) -
(6480000*((17*pi)/60 + arg(x(1)*i + x(2) - 259 - 1571*i))*(imag(x(1)) - real(x(2)) + 259))/(169*pi
Error in fsolve (line 241)
fuser = feval(funfcn{3},x,varargin{:});
Caused by:
Failure in initial user-supplied objective function evaluation. FSOLVE cannot continue.
'
Please help me out in this. Thanks

  5 Comments

Please format the code using the 'Code' button, it is very unreadable.
Sorry for the inconvenience, Now i made it correct. Please look into it.
? Your current function has no reference to arg(). Are you possibly using matlabFunction() to generate the function in some code you have not shown here? The myfun() you have shown here has no relationship to finding S or Sx or Sy.

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1 Answer

Answer by Shashank Prasanna on 29 Apr 2013

Satendra, arg is not a function in MATLAB but you the function 'angle' computes the argument of the complex number which I believe you are trying to find. In your 'S' replace 'arg' with 'angle'

  1 Comment

Thanks Shashank, But when i did that i got following error message:
Undefined function 'atan2' for input arguments of type 'sym'.
Error in angle (line 14)
p = atan2(imag(h), real(h));

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