I Is there a typo in the formula for dividing complex numbers?

[Drakkith]

Quick question. While going over complex numbers in my book, I think I came across a typo and I wanted to be sure I had the right information. In the paragraph going over dividing complex numbers, my book has:
$|\frac{z_1}{z_2}|=|\frac{z_1}{z_2}|$

That's obviously true. Should that be $|\frac{z_1}{z_2}|=\frac{|z_1|}{|z_2|}$ instead?

 

[jedishrfu]

You're reading the Schaum's Outline on Complex Numbers! I saw that too!

Yes that is a typo!

Its easy to prove using Euler's notation for complex numbers: $z = r e^{i \theta}$

 

[Drakkith]

You're reading the Schaum's Outline on Complex Numbers! I saw that too!

Actually I'm reading Kreyszig, Advanced Engineering Mathematics, 10th Edition.

Yes that is a typo!

Its easy to prove using Euler's notation for complex numbers: $z = r e^{i \theta}$

Thanks, Jedi!

 

[Mark44]

Actually I'm reading Kreyszig, Advanced Engineering Mathematics, 10th Edition.

I have the 3rd edition of this book, which doesn't have this typo.
You might find it interesting that I paid $14.95 for the book, but that was in 1972...

 

[Drakkith]

I have the 3rd edition of this book, which doesn't have this typo.
You might find it interesting that I paid $14.95 for the book, but that was in 1972...

I'm using an online version that came packaged with a code for the program we use for receiving and submitting our homework. Apparently the physical textbook that also came with the package either isn't the same textbook, or it's an edited/shortened version, as it doesn't even have the chapter on complex numbers in it. The physical book has chapters 1-8 that appear to follow the online version, but complex numbers are in chapter 13 in the online book, which is where the error is at. Had I known that I was getting shafted I would have purchased the code and the full book separately from each other.