# Math Help - Norm of a function?

1. ## Norm of a function?

I'm confused about norms. I have

1) $A=1-ic\sin\theta$

2) $\parallel A \parallel = 1+c^2\sin^2\theta$

How does one get from 1) to 2)? What kind of norm would this be? (i is imaginary number)

2. ## Re: Norm of a function?

Originally Posted by Jason Bourne
I'm confused about norms. I have

1) $A=1-ic\sin\theta$

2) $\parallel A \parallel = \color{blue}\sqrt{1+c^2\sin^2\theta}$

How does one get from 1) to 2)? What kind of norm would this be? (i is imaginary number)
First, note the correction above.

It is the case that for any complex number $\|a+b\mathbf{i}\|=\sqrt{a^2+b^2}$

Also note than many textbooks use $|A|$ instead of $\|A\|$.