5-Day Free Trial
5-day free, full-access trial TTP
Available with Beat the GMAT members only code
MORE DETAILS
Vague PS
This topic has expert replies
-
cans
- Legendary Member
- Posts: 1309
- Joined: Mon Apr 04, 2011 5:34 am
- Location: India
- Thanked: 310 times
- Followed by:123 members
- GMAT Score:750
x' = x+1
(x+1)^2 - (x^2)'
= x^2 + 2x + 1 - (x^2 + 1) = 2x
IMO D
(x+1)^2 - (x^2)'
= x^2 + 2x + 1 - (x^2 + 1) = 2x
IMO D
If my post helped you- let me know by pushing the thanks button 
Contact me about long distance tutoring!
[email protected]
Cans!!
Contact me about long distance tutoring!
[email protected]
Cans!!
-
GmatMathPro
- GMAT Instructor
- Posts: 349
- Joined: Wed Sep 28, 2011 3:38 pm
- Location: Austin, TX
- Thanked: 236 times
- Followed by:54 members
- GMAT Score:770
I don't really know how to type this notation, so let's do it this way...
Treat the definition of "x with a bar" the same way you would treat a function definition. This question would be the same as saying f(x)=x+1. Which of the following is equal to [f(x)]^2-f(x^2).
[f(x)]^2-f(x^2)=
(x+1)^2-(x^2+1)=
x^2+2x+1-x^2-1=
2x
ans: D
Treat the definition of "x with a bar" the same way you would treat a function definition. This question would be the same as saying f(x)=x+1. Which of the following is equal to [f(x)]^2-f(x^2).
[f(x)]^2-f(x^2)=
(x+1)^2-(x^2+1)=
x^2+2x+1-x^2-1=
2x
ans: D
-
fcabanski
- Master | Next Rank: 500 Posts
- Posts: 104
- Joined: Fri Oct 07, 2011 10:23 pm
- Thanked: 36 times
- Followed by:4 members
The problem is just trying to confuse you by using x bar as the notation for f(x) or y, a function. Whenever there's a strange function notation problem, replace that strange figure with f(x) or y so the notation looks familiar.
-
GMATGuruNY
- GMAT Instructor
- Posts: 15539
- Joined: Tue May 25, 2010 12:04 pm
- Location: New York, NY
- Thanked: 13060 times
- Followed by:1906 members
- GMAT Score:790
If @x = x+1, which of the following is equal to (@x)² - @(x²) for all values of x?
Let x=3:
(@3)² - @(3²)
= (3+1)² - @9
= 16 - (9+1)
= 6. This is our target.
Now we plug x=3 into the answers to see which yields our target of 6.
Only answer choice D works:
2x = 2*3 = 6.
The correct answer is D.
Let x=3:
(@3)² - @(3²)
= (3+1)² - @9
= 16 - (9+1)
= 6. This is our target.
Now we plug x=3 into the answers to see which yields our target of 6.
Only answer choice D works:
2x = 2*3 = 6.
The correct answer is D.
Private tutor exclusively for the GMAT and GRE, with over 20 years of experience.
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
Student Review #1
Student Review #2
Student Review #3
