Why Undefined operator '==' for input arguments of type 'function_handle'

Why do I receive the following error every time I run? "Why Undefined operator '==' for input arguments of type 'function_handle'"

Y = @(m,y) sin(theta)*m - cos(theta)*m - Q/(2*pi)*atan((m/y))
x=[];
for y = -100:0.1:100
x=[x; fzero(@(m,y) Y,25)];
end

Thanks, Eric

Answer 1

[Star Strider]

The fzero function solves for functions of one variable. You have two, so you would have to use fsolve or another optimisation function, and you have to address them as a vector of parameters for any of the optimisation functions to work.

I have no idea what you want to do, but this is one approach that will probably work:

Q = ...;
theta = ...;
m = ...;
Y = @(m,y) sin(theta)*m - cos(theta)*m - Q./(2*pi)*atan((m./y));
x=[];
for y = -100:0.1:100
    yi = fzero(@(y) Y(m,y),25)
    x=[x; yi];
end

[Eric Daiber]

So I put this into Matlab and the error showing up now is: Operands to the and && operators must be convertible to logical scalar values.

Error in fzero (line 306) elseif ~isfinite(fx) ~isreal(fx)

Error in Trial3 (line 12) yi = fzero(@(y) A(m,y),25)

What is wrong? I am new to this.

[Star Strider]

In the code you posted, you did not state what ‘Q’, ‘theta’, and ‘m’ are, so I suspect the problem is with one of them and the result of the calculations with them in your ‘Y’ function.

Please describe a bit about what you’re doing. That would help me discover where the problems may be.

Also, to clarify:

Q./(2*pi)*atan((m./y))     is the same as     atan(m./y)*Q./(2*pi)

Is that what you intend?