- 1
√(2n+1)
√(n+1)/√n
√(n+1) - √n
√(n+1) = √n
I understand how the OG explains the answer, but do you have any simpler tips?
OA: E
Source: OG 12th E; PS #117
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Computation with radical expressions
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jeffedwards
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If n is positive, which of the following is equal to 1/((√(n+1)) - √n)
I understand how the OG explains the answer, but do you have any simpler tips?
OA: E
Source: OG 12th E; PS #117
I understand how the OG explains the answer, but do you have any simpler tips?
OA: E
Source: OG 12th E; PS #117
Multiply the whole equation by
(√(n+1) + √n)/(√(n+1) + √n)
You'll get:
(√(n+1) + √n)/(n + 1 - n)
Which is just:
√(n+1) + √n
This is basically testing whether you know that (x-y)*(x+y)= x^2 - y^2
(√(n+1) + √n)/(√(n+1) + √n)
You'll get:
(√(n+1) + √n)/(n + 1 - n)
Which is just:
√(n+1) + √n
This is basically testing whether you know that (x-y)*(x+y)= x^2 - y^2
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jeffedwards
- Master | Next Rank: 500 Posts
- Posts: 109
- Joined: Mon Oct 12, 2009 4:58 am
- Thanked: 12 times
- Followed by:1 members
- GMAT Score:720
thanks a million. that is so simple. I should have known they were testing for that. i've got to be on the lookout for GMAC's little tricks. Thanks a ton!!
