solve the question ( fsolve , vpasolve)

4 次查看（过去 30 天）
onur karakurt
onur karakurt 2021-5-22
编辑： Torsten 2021-5-23
is there any other way to solve the equation below.
clear all;clc;
a=0.5;
x=linspace(-2*a,2*a,100);
eqn=@(x,y,a)(y.^2./(x.^2+y.^2)).*(1-2.*(1-(x./(2*a)).^2-(y./(2*a)).^2))-(y./a).^2;
for k = 1:numel(x)
options = optimoptions('fsolve','Display','iter');
yv(k,:) = fsolve(@(y)eqn(x(k),y,a), 1, options);
end
plot(x,yv)
when ı change initial value for iteration, answers and graph is changing.
  3 个评论
显示 1更早的评论
Torsten
Torsten 2021-5-23
编辑：Torsten 2021-5-23
If you multiply your equation by x^2+y^2, you see that you try to solve a quadratic equation in y^2. This equation might have 0, 1, 2 or 4 real solutions. Use symbolic computation using "solve" instead of "fsolve" to sort out the solution that makes sense for your problem.
Torsten
Torsten 2021-5-23
编辑：Torsten 2021-5-23
Solving your equation by hand gives y=0 as the only solution for all values of a and x different from 0. For x=0, no solution for y exists.

请先登录，再进行评论。

请先登录，再回答此问题。

回答（1 个）

John D'Errico
John D'Errico 2021-5-22
I think you do not understand optimization. When you change the initial value, it is EXPECTED that the solver MAY converge to a different solution.
  2 个评论
onur karakurt
onur karakurt 2021-5-22
solve function is not sufficient to answer the question, ı tried this fsolve function. How can I get correct y values.
onur karakurt
onur karakurt 2021-5-22
what is the correct function to solve the equation

请先登录，再进行评论。

类别

在 Help Center 和 File Exchange 中查找有关 Symbolic Math Toolbox 的更多信息

标签

产品


版本

R2020a

Community Treasure Hunt

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

Start Hunting!

Translated by