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# If x + y = a and x тАУ y = b, then 2xy

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Manager
Joined: 07 Jul 2003
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If x + y = a and x тАУ y = b, then 2xy [#permalink]

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18 Feb 2004, 12:00
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

If x + y = a and x тАУ y = b, then 2xy =

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Senior Manager
Joined: 05 May 2003
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Location: Aus

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18 Feb 2004, 13:32
2xy = a power 2 - (x power 2 + y power 2 )
or
2xy = (x power 2 + y power 2) - b power 2

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Senior Manager
Joined: 23 Aug 2003
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18 Feb 2004, 13:49
x + y = a
x тАУ y = b

2x=a+b x=a+b/2
2y = a-b y=a-b/2

2xy =(a+b/2) * (a-b/2)
2xy = 2/4((a+b)*(a-b))

2xy = 1/2(a^2-b^2)

Vivek.
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"Start By Doing What Is Necessary ,Then What Is Possible & Suddenly You Will Realise That You Are Doing The Impossible"

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Senior Manager
Joined: 30 Aug 2003
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18 Feb 2004, 14:06
I got the same...a^2 -b^2/2
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shubhangi

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18 Feb 2004, 14:06
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