Why doesn't f(alpha) act like a function?

edit

To display blocks of code or error messages, skip a line above and below, and do one of the following (all give the same result):

• indent all code lines with 4 spaces
• select all code lines and click the "code" button (the icon with '101 010')
• select all code lines and hit ctrl-K

For instance, typing

If we define `f` by

    def f(x, y, z):
        return x * y * z

then `f(2, 3, 5)` returns `30` but `f(2*3*5)` gives:

    TypeError: f() takes exactly 3 arguments (1 given)

produces:

If we define f by

def f(x, y, z):
    return x * y * z

then f(2, 3, 5) returns 30 but f(2*3*5) gives:

TypeError: f() takes exactly 3 arguments (1 given)

Please edit your question to do that.