1. The problem statement, all variables and given/known data Find the least squares approximation of cos^3(x) by a combination of sin(x) and cos(x) over the interval (0, 2pi) 2. Relevant equations 3. The attempt at a solution I know how to find a least squares approximation with vectors, but I don't even know how to start with a function? The normal equation wouldn't work here because there are no vectors correct? The answer in the back of the book gives sin (x)+(3/4)cos(x), but I don't even know what that answer means. Please help.