Magnitude of this complex number

[henryc09]

Homework Statement

I have this equation and need to find |F|² (which should be real). I thought you did this by multiplying by the complex conjugate which was just replacing all i with -i, but this doesn't seem to work. What am I doing wrong?

Thanks

Homework Equations

The Attempt at a Solution

 

[rock.freak667]

You might need to apply Euler's formula and then apply F= A/B => |F| = |A|/|B|.