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## #1 2018-04-03 01:45:36

BLANK
Guest

### Help, please!

Prove that if w,z are complex numbers such that |w|=|z|=1 and wz!= -1, then (w+z)/(1+wz) is a real number.

## #2 2018-04-03 23:36:31

bob bundy
Administrator
Registered: 2010-06-20
Posts: 8,322

### Re: Help, please!

hi BLANK,

Welcome to the forum.

I think this has been asked before and fairly recently but I haven't managed to find it yet.  You have typed

wz!= -1

which seems like a typo.  ! would be 'factorial' and that makes no sense in this context.  If we drop the ! then wz = -1 and that also makes no sense as it makes the denominator of the expression zero.

Please respond with a clarification.

Bob

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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## #3 2018-04-04 21:08:14

bob bundy
Administrator
Registered: 2010-06-20
Posts: 8,322

### Re: Help, please!

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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## #4 Yesterday 06:00:54

dogleg
Member
Registered: Yesterday
Posts: 1

### Re: Help, please!

Hi. I am new to this forum and very rusty in my math. I am trying to relearn roots of expressions like     : Square root of  x-3 =     , and fourth root of x-3   for example.  Help me get started please.

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## #5 Yesterday 19:26:10

bob bundy
Administrator
Registered: 2010-06-20
Posts: 8,322

### Re: Help, please!

hi dogleg,

Did you mean

Have a look here:

http://www.mathsisfun.com/exponent.html

Bob

Children are not defined by school ...........The Fonz
You cannot teach a man anything;  you can only help him find it within himself..........Galileo Galilei

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