# I have forgotten my complex calculus!

1. Nov 5, 2008

### mhicks3

Can anyone help me with a complex calculus concept? I took this class years ago and cannot remember how to simplify something like $$\left|cos(1+2i)\right|$$^2?

Thanks!

Michael

2. Nov 5, 2008

### Office_Shredder

Staff Emeritus
If a is a complex number, |a|2 = a * conjugate(a)

where if a=x+iy, conjugate(a) = x-iy.

So re-write cos(1+2i) in terms of exponentials and multiply.... something good probably comes out the other side

3. Nov 5, 2008

### mhicks3

Thanks! I'll try that. I think I actually remember now.

Michael

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