how to use fsolve in for loop?

I need to pass different values of (theta_r) into F(1) and F(2) to get different values of x(1) and x(2).

i use this code, but it shows me many errors.

clear all;
%defining the parameters.
global R  L3 L4 L5  theta_r 
R=80;  L5=360;   L4=360;    L3=120;   n=2;    m=100*n;  
theta_r=linspace(0,2*pi*n,m);

function F = value(x,theta_r)
F(1)=R*sin(theta_r)+L3*sin(x(1))-L5*sin(x(2));
F(2)= R*cos(theta_r)+L3*cos(x(1))-L5*cos(x(2))-L4;
end
for b = 1:numl(theta_r)
    x(b,:)=fsolve(@(x)value(x,theta_r(b),[1,0]));
end

[Luqman Alabri]

How can I fix this?

Answer 1

[Jan]

global R  L3 L4 L5
R=80;  L5=360;   L4=360;    L3=120;   n=2;    m=100*n;  
theta_r=linspace(0,2*pi*n,m);

for b = 1:numel(theta_r)   % fixed: "numl"
    x(b,:) = fsolve(@(x) value(x, theta_r(b)), [1,0]);
end

function F = value(x,theta_r)
global R  L3 L4 L5
F(1)=R*sin(theta_r)+L3*sin(x(1))-L5*sin(x(2));
F(2)= R*cos(theta_r)+L3*cos(x(1))-L5*cos(x(2))-L4;
end

[Luqman Alabri]

Thank you so much.

[Luqman Alabri]

Hello Jan,

How to make sure that the angles x(1) and x(2) were mesured from the positive x axis, because when I plot input versus output there were some incorrect values of x(1) and x(2).

like this:

[Torsten]

You could try

initial = [1,0];
for b=1:numel(theta_r)
     x(b,:) = fsolve(@(x) value(x,theta_r(b),initial);
     initial = x(b,:);
end

[Jan]

@Torsten: A good idea.

[Luqman Alabri]

Thank you all.