x' = x+1
(x+1)^2 - (x^2)'
= x^2 + 2x + 1 - (x^2 + 1) = 2x
IMO D
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Cans!!
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GmatMathPro
- GMAT Instructor
- Posts: 349
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- 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
-
GMATGuruNY
- GMAT Instructor
- Posts: 15539
- Location: New York, NY
- Thanked: 13060 times
- 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.
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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
