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Exponent values-GMATPREPI

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Source: — Problem Solving |

Re: Exponent values-GMATPREPI

by sudhir3127 » Mon Aug 18, 2008 8:05 pm
medea66 wrote:How do you solve for this?
i am sure the question shud read like this ...

2^(x + Y)^2)/2^(x - Y)^2 ...

anyways here we go

2^((x+y)^2 - (x-y)^2)

2^(x^2 + 2xy + y^2 - x^2 + 2xy - y^2)

2^(4xy)

2^4*1 = 16..

hope this helps.. i am sure after u see the question in the right way ..its not at all difficult
Last edited by sudhir3127 on Mon Aug 18, 2008 8:37 pm, edited 1 time in total.
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Re: Exponent values-GMATPREPI

by uncbeers » Mon Aug 18, 2008 8:23 pm
sudhir3127 wrote:
medea66 wrote:How do you solve for this?
i am sure the question shud read like this ...

2^(x + Y)^2)/2^(x - Y)^2 ... GMAT PREP we dont except this!!!!!!

anyways here we go

2^((x+y)^2 - (x-y)^2)

2^(x^2 + 2xy + y^2 - x^2 + 2xy - y^2)

2^(4xy)

2^4*1 = 16..

hope this helps.. i am sure after u see the question in the right way ..its not at all difficult
What is different from the problem in GMATPrep and the way you wrote it? I think it is the corrected form of the problem.

Also, shouldn't that second 2xy be a -2xy in [2^(x^2 + 2xy + y^2 - x^2 + 2xy - y^2) ]? That way it is 2^ (2xy - (-2xy)) to become 2^(4xy)?

(x+y)^2 = x^2 + 2xy + y^2
(x-y)^2 = x^2 -2xy + y^2


Hope that is right...
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Re: Exponent values-GMATPREPI

by sudhir3127 » Mon Aug 18, 2008 8:39 pm
uncbeers wrote:
sudhir3127 wrote:
medea66 wrote:How do you solve for this?
i am sure the question shud read like this ...

2^(x + Y)^2)/2^(x - Y)^2 ...

anyways here we go

2^((x+y)^2 - (x-y)^2)

2^(x^2 + 2xy + y^2 - x^2 + 2xy - y^2)

2^(4xy)

2^4*1 = 16..

hope this helps.. i am sure after u see the question in the right way ..its not at all difficult
What is different from the problem in GMATPrep and the way you wrote it? I think it is the corrected form of the problem.

Also, shouldn't that second 2xy be a -2xy in [2^(x^2 + 2xy + y^2 - x^2 + 2xy - y^2) ]? That way it is 2^ (2xy - (-2xy)) to become 2^(4xy)?

(x+y)^2 = x^2 + 2xy + y^2
(x-y)^2 = x^2 -2xy + y^2


Hope that is right...
ur right on 2xy -(-2xy) .. If u see i have already factored in that step and done the calculation...
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by medea66 » Wed Aug 20, 2008 5:56 pm
So how do you get 2^4*1 = 16 from 2^(4xy)? Where does the 1 come from?
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by pepeprepa » Thu Aug 21, 2008 1:49 am
xy=1 comes from the question :wink:
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by medea66 » Thu Aug 21, 2008 5:33 pm
Oh, duh, that was a stupid question on my part.
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