# Norm of a function?

• September 26th 2011, 05:52 AM
Jason Bourne
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)
• September 26th 2011, 06:25 AM
Plato
Re: Norm of a function?
Quote:

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 $\|A\|$.