Matlab：使用fzero解隐式方程时出错

Question

Equation is:

where, a and b are constants and both equal to 0.0130

This is the code I am using:

% Solving the equation for zero.
f = @(theta) ((a+b).*theta)./((theta.^2)-(a.*b)) - tan(theta);  % Notice the dots (.)

% Now plot it to get an idea of where the zeros are.
theta = 0:1:100;
for i=1:length(theta)
    hold on
    plot(theta(i),f(theta(i)),'-o')  % Look for the zeros
end

% Now find the roots.
cnt = 1;
for ii = [0,2,50]  % This vector has the guesses.
    rt(cnt) = fzero(f,ii); % Pass each guess to FZERO.
    cnt = cnt + 1;
end

This is the error I get:

??? Operands to the || and && operators must be convertible to
logical scalar values.

Error in ==> fzero at 323
    elseif ~isfinite(fx) || ~isreal(fx)

Error in ==> HW4 at 52
    rt(cnt) = fzero(f,ii); % Pass each guess to FZERO.

I would like to get the first solution of \\theta. Thanks.

Answer 1

This code works for me with no errors (I wrote the value 0.0130 instead of a and b). Check that you're not using some other variable name in your code, or not clearing some variables...