Need help please with this program for Newton Raphson method

Question

bingo 2013-11-14

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/106178-need-help-please-with-this-program-for-newton-raphson-method

评论： bingo 2013-11-15

Hi, i've got this program. For some equations it works well, for others not. It gives me this:

??? Error using ==> inline.subsref at 17
Too many inputs to inline function.

and

Error in ==> Untitled8b at 18
    fpxo=jf(xo(1),xo(2));

I know maybe it's for the use of inline, pheraps i should have used anonymous function but i couldn't do it.

this is the code(with an example working equations):

clear all
xo=[5;5] ;
syms x1 x2
fname=[(10*x1^2+2*x1-14*x1*x2-3*x2-2+x2)*0+x1;
   3*(x1^3)*x2+5*x1^2-x2^3+7*x2-220];
fprima=jacobian(fname);
 epsilon=1.e-10;
 maxiter = 30;
 iter = 1;
 f=inline(fname,'x1','x2');
 jf=inline(fprima);
 error=norm(f(xo(1),xo(2)),2);
 fprintf('error=%12.8f\n', error);
 while error >= epsilon
    fxo=f(xo(1),xo(2));
    fpxo=jf(xo(1),xo(2));
    x1=xo-inv(fpxo)*fxo;
    fx1=f(x1(1),x1(2));
    error =norm((fx1),2);%abs(x1-xo);
    fprintf(' Iter %2d  raiz x=(%14.9f,%14.9f) f(x)=(%14.9f,%14.9f)\n',....
          iter,x1(1),x1(2),fx1(1),fx1(2));
    if iter > maxiter
        fprintf(' Numero di iterazioni massime superato \n');
    return;
    end
    xo=x1;
    iter=iter+1;
 end