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SoftwareDrone
- Junior | Next Rank: 30 Posts
- Posts: 22
- Joined: Thu Jun 21, 2012 1:25 pm
- Location: San Jose, CA
- GMAT Score:430
After completing the GMAT Prep Now video sessions, I am happy to report that I scored a 640 on my practice test today. This is great, considering my first (and only so far) attempt at the GMAT (before the GMAT Prep Now videos) yielded a 430. There were two math problems in particular that didn't seem so difficult at first glance, yet I cannot seem to push through. This first one is difficult to convert to pure text, but I'll try:
Evaluate (2^((x+y)^2))/(2^((x-y)^2)) given that x*y = 1.
In other words, take x+y. Square that so you get (x+y) squared. Well, it's 2 to the power of all that. 2 to the power of (x+y) squared. That is the numerator. The demoninator is the same except x-y instead of x+y.
I expand the x+y squared and the x-y squared to get (x+y)(x+y) / (x-y)(x-y).
Then, I multiply to get x^2 + 2xy + y^2 / x^2 - 2xy + y^2.
Since x*y = 1, I get x^2 + 2 + y^2 / x^2 - 2 + y^2.
and that is where I'm stuck.
Any hints would be appreciated.
Evaluate (2^((x+y)^2))/(2^((x-y)^2)) given that x*y = 1.
In other words, take x+y. Square that so you get (x+y) squared. Well, it's 2 to the power of all that. 2 to the power of (x+y) squared. That is the numerator. The demoninator is the same except x-y instead of x+y.
I expand the x+y squared and the x-y squared to get (x+y)(x+y) / (x-y)(x-y).
Then, I multiply to get x^2 + 2xy + y^2 / x^2 - 2xy + y^2.
Since x*y = 1, I get x^2 + 2 + y^2 / x^2 - 2 + y^2.
and that is where I'm stuck.
Any hints would be appreciated.
