Abs "too many input arguments"

I am taking a Engineering Computation college course and I'm very new to Matlab. I cannot take the absolute value of a vector as it keeps telling me too many input arguments. I need to take the negative values of the vector and change them to positive, if there is another way to do this I would like to know as well. Thank you!

[Alexandra Harkai]

What is the code where you're getting the error?

Answer 1

[Steven Lord]

This:

abs(1, -2, 3)

is very different from this:

abs([1, -2, 3])

The former will throw the "too many input arguments" error you received because you're trying to call abs with three input arguments, each of which is a 1-by-1 array (a scalar.)

The latter will return a 1-by-3 array because you called abs with one input argument and that input argument was a 1-by-3 array (a vector.)

The documentation for the abs function does not show a three input syntax as being supported, it only shows a one input syntax.