# Not sure how to solve this problem

#### belleamie

not sure how to solve this problem, Any suggestions or examples?

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#### marlon

you should have posted this in the homework section.

What do you know on complex algebra ?

marlon

#### Gokul43201

Staff Emeritus
Gold Member
(This is not Quantum Physics - moving to homework help)

The question is wrongly written. It is asking you to show that the modulus of the product of 2 complex numbers is equal to the product of their moduli, and that the argument is equal to the sum of their arguments.

#### belleamie

marlon said:
you should have posted this in the homework section.

What do you know on complex algebra ?

marlon
Hmm the problem was a review question for my quantum 1 class which is why i posted it here. Since I wasnt sure exactly where in my book it refered to it. I'm taken up to linear algebra a couple yrs ago. I cut and pasted thequestion as it was typed in my notes...

#### Gokul43201

Staff Emeritus
Gold Member
What happens if you write the complex numbers in the polar (exponential) form ?

#### belleamie

Gokul43201 said:
What happens if you write the complex numbers in the polar (exponential) form ?
I'm not sure how to write it in that form

#### Curious3141

Homework Helper
belleamie said:
I'm not sure how to write it in that form
$$z = r(\cos \theta + i\sin \theta) = re^{i\theta}$$

#### Gokul43201

Staff Emeritus
Gold Member
belleamie said:
I'm not sure how to write it in that form
In that case, you need to go over your chapter on complex analysis from the start. If you do not know the basics of complex numbers, you will not get anywhere by cutting and pasting solutions.

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