how to add a matrix element in a fzero function

Hi guys,

i m trying to solve x*besselj(1,x)/besselj(0,x)-J(m) using fzero function

My code is

n = 100;
J = [0.5 2 5 10 20 30 50 100];
for i = 1:n
        A(i,1)=fzero('x*besselj(1,x)/besselj(0,x)-J(1)',i);
end
for i = 1:n
        A(i,2)=fzero('x*besselj(1,x)/besselj(0,x)-J(2)',i);
end
for i = 1:n
        A(i,3)=fzero('x*besselj(1,x)/besselj(0,x)-J(3)',i);
end
for i = 1:n
        A(i,3)=fzero('x*besselj(1,x)/besselj(0,x)-J(4)',i);
end
for i = 1:n
        A(i,3)=fzero('x*besselj(1,x)/besselj(0,x)-J(5)',i);
end
for i = 1:n
        A(i,3)=fzero('x*besselj(1,x)/besselj(0,x)-J(6)',i);
end
for i = 1:n
        A(i,3)=fzero('x*besselj(1,x)/besselj(0,x)-J(7)',i);
end
for i = 1:n
        A(i,3)=fzero('x*besselj(1,x)/besselj(0,x)-J(8)',i);
end

i am trying to write the code above

n = 100;
J = [0.5 2 5 10 20 30 50 100];
for j = 1:8
    for i = 1:n
        A(i,m)=fzero('x*besselj(1,x)/besselj(0,x)-J(m)',i);
    end
end

like that. when i run the code i get this error;

Error using fzero (line 306)
FZERO cannot continue because user-supplied expression ==> x*besselj(1,x)/besselj(0,x)-J(m) failed with the error below.

 Error in inline expression ==> x*besselj(1,x)/besselj(0,x)-J(m)
 Undefined function or variable 'm'.

Error in Untitled (line 6)
        A(i,m)=fzero('x*besselj(1,x)/besselj(0,x)-J(m)',i);

Can you help to solve this.

Thanks

Answer 1

[dpb]

As you wrote it, the function is the literal text including the argument so nothing ever gets substituted for dynamically--one way that mimics yours directly but does get the current value of J() would be

...
for i = 1:n
  fnA=@(x) x*besselj(1,x)/besselj(0,x)-J(i);
  A(i,n)=fzero(fnA,0);
end

that embeds current J(i) into the function handle.

I just used a constant zero for the initial guess, that worked for the first couple; I didn't check if need better for the full range...

[dpb]

many thanks for your answer, i solved it [-- Answer moved to comment dpb]