Replacing symbolic variable with function input

Hi, I'm trying to replace my symbolic variable with whatever value is input into the function.

Here's some sample code:

function y=TestFunction(x)
syms G
y=G.^2
end

My result ends up having coefficients and is strictly in terms of G yet I can't figure out how to replace G with the input/function variable x. I tried doing subs but the documentation is a little confusing. I tried

x=G
y=subs(y)

as well as

x=G
subs(y,G,x)

I've probably gone through every possibility/variation of subs except the right one. I suspect it's painfully simple. Anyone have any ideas? I'm thinking there might be a way to do this without having G be symbolic but it eludes me.

Obviously the actual code is much longer but this is the issue summarized.

Thanks!

Answer 1

[Steven Lord]

For your sample code, you don't need to use syms at all.

function y = TestFunction(x)
y = x.^2;
end

Show an example that's somewhat closer to your actual problem and we may be able to offer some suggestions.