MATLAB Answers

How do I get real roots only from the Newton Raphson method for solving multivariable equation?

22 ビュー (過去 30 日間)
Anik Faisal
Anik Faisal 2018 年 8 月 10 日
コメント済み: Walter Roberson 2018 年 8 月 11 日
Hi All,
I'm using the following lines of codes to call on the new_raph.m function to get solutions for x & y.
b0=1;
z=linspace(0.5,1,2);
u0=(b0/2/pi).*asin(z);
x0=linspace(.1,.9,length(z)); y0=linspace(1*exp(1),5*exp(1),length(z));
syms x y
assume(x,'real')
assume(y,'real')
for j=1:length(z)
equation1=2.*x.*log(y)-(pi*y.^2.*z(j))+(y.^2.*asin(z(j)).*sin(2.*pi.*(u0(j)+x)/b0));
equation2=x.^2./y-2*pi.*y.*z(j).*x+2.*y.*(cos(2*pi.*u0(j)./b0)-cos(2.*pi.*(u0(j)+x)./b0));
[p(j) q(j)]=new_raph(equation1, equation2, x0(j),y0(j));
end
I only want real roots but the function is giving me complex roots. Can anyone suggest a better way of doing this where I can get real numbers only for the system of equations? Thanks!

  1 件のコメント

Walter Roberson
Walter Roberson 2018 年 8 月 11 日
Never eval() a symbolic expression. Symbolic expressions are in a language which is not quite MATLAB.
Use \ in preference to inv() as inv() introduces inaccuracies.

サインインしてコメントする。

回答 (0 件)

Community Treasure Hunt

Find the treasures in MATLAB Central and discover how the community can help you!

Start Hunting!

Translated by