MATLAB: How to Generate a Random # Between -1 and 1

Question

Hello,

I have a simple question. I want to produce a random number between -1 and 1 as the title states. I tried doing this already:

randnum = rand(1)

But this will always be positive because it will generate between 0 and 1. So I tried this:

randnum = rand([-1,1])

But I receive an empty, double column vector.

Answer 1

Did you look in the help where is told you how to get a number in the range from a to b?

r = 2 * rand - 1;