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## #1 2005-09-16 23:42:17

tilly
Guest

### Rationalising denominators.

hey, i was wondering if you could show me how to rationalise the denomiators on a couple of these, in easy steps.
1
----
√ 2

√ 2
------
3√ 3

√ 43 - √ 23
-------------
√ 43 + √ 23

## #2 2005-09-17 01:01:07

MathsIsFun
Administrator
Registered: 2005-01-21
Posts: 7,657

### Re: Rationalising denominators.

As in getting rid of radicals in the denominator?

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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tilly
Guest

yes, please help

## #4 2005-09-17 20:02:26

MathsIsFun
Administrator
Registered: 2005-01-21
Posts: 7,657

### Re: Rationalising denominators.

√ 2
------
3√ 3

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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tilly
Guest

cheers

## #6 2005-09-28 02:48:16

mathsyperson
Moderator
Registered: 2005-06-22
Posts: 4,900

### Re: Rationalising denominators.

√43 - √23        √43 - √23     43 - 2√(43x23) + 23      66 - 2√989
------------- x  ------------ = ------------------------ =  -------------
√43 + √23       √43 - √23              43 - 23                      20

The math tag looks rather complex.

Why did the vector cross the road?
It wanted to be normal.

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## #7 2005-10-06 04:32:27

ramzi
Member
Registered: 2005-10-05
Posts: 1

### Re: Rationalising denominators.

Clever maths people, how do you deduce (-1) x (-1)= 1

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## #8 2005-10-06 10:00:07

MathsIsFun
Administrator
Registered: 2005-01-21
Posts: 7,657

### Re: Rationalising denominators.

A baby taught us, see Multiplying Negatives

"The physicists defer only to mathematicians, and the mathematicians defer only to God ..."  - Leon M. Lederman

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