Conjugates with Square Roots

Date: 1/29/96 at 9:59:14
From: Anonymous
Subject: square root and conjugate

I don't understand what conjugates are in relation to square 
roots, and what good they do. 

Date: 3/27/96 at 23:54:26
From: Doctor Jodi
Subject: Re: square root and conjugate

Hi there! 

Okay, let me write square root of x as x^1/2

Now, suppose I have a fraction:

         1
    ------------
     2^(1/2) -3

Suppose I want to get the square root out of the denominator....
 
To do that, we can use the conjugate (square root of 2 PLUS 3):

  1                 2^(1/2) + 3
-----------   *    ---------------
2^(1/2) -3          2^(1/2) + 3

Do you see what we'll get?

Write back if you have more questions or want to know more.

I hope this helps.

-Doctor Jodi,  The Math Forum