MATLAB: Error: Unexpected MATLAB expression.

Question

I simply do not understand how there is an error here,

>> f = symsum((1/(2*n-1))*sin((2*n-1)2*x), n, 1, 5)

                                 ↑ Error: Unexpected MATLAB expression.

To clarify the arrow is pointing at the "2" next to "x".

Edit: I have defined x and n as symbolic, but the error still occurs.

Answer 1

You have not defined n and x as symbolic.

syms n x
f = symsum((1/(2*n-1))*sin((2*n-1)*2*x), n, 1, 5)