# Trying to write a function using @

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ssmith on 17 Nov 2021
Commented: John D'Errico on 17 Nov 2021
I am trying to write this function in my code but I am getting an invalid MATLAB syntax error. The equation is g(x) = sin(x)/x
Here is what I have:
g = @x sin(x)/x
g(1)
g(pi)
The g(1) and g(pi) are to be used calling the function to solve.

Stephen23 on 17 Nov 2021
Edited: Stephen23 on 17 Nov 2021
g = @(x) sin(x)/x;
% ^ ^ you forgot these
g(1)
ans = 0.8415
g(pi)
ans = 3.8982e-17
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John D'Errico on 17 Nov 2021
A good addendum is that IF you want this function to be vectorized, thus able to work for an entire vector or array of inputs elements, then use the ./ operator. Thus:
g = @(x) sin(x)./x;
(Without that dot in there, you will get strange results when you try to use this function on a vector.) But now we can use g on entire vectors.
g([1 2 3 4 5])
ans = 1×5
0.8415 0.4546 0.0470 -0.1892 -0.1918
The singularity at x==0 is unresolved of course, since 0/0 is undefined..
g(0)
ans = NaN
We can even plot it nicely without any arguments from MATLAB, thus
fplot(g,[-10*pi,10*pi]) 