It is currently 19 Nov 2017, 15:04

### GMAT Club Daily Prep

#### Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# unsolved challenge problem

Author Message
Director
Joined: 09 Aug 2006
Posts: 521

Kudos [?]: 111 [0], given: 0

### Show Tags

22 Jul 2007, 05:58
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Hi Guys,
the problem in below has not reached a conclusion on why E is wrong. could anyone help..

http://www.gmatclub.com/phpbb/viewtopic ... =challenge

Kudos [?]: 111 [0], given: 0

Manager
Joined: 08 Jul 2007
Posts: 173

Kudos [?]: 11 [0], given: 0

### Show Tags

22 Jul 2007, 07:00
function f (x) SATISFIES f (x) =f (x)^2 FOR ALL x which of the following must be true

f(4) = f(2)*f(2)
f(16) - f(-2) = 0
f(-2) + f(4) = 0
f(3) = 3*f(3)
f(0) = 0

E is not necessarily true. It depends on the function. For example, if the function were such that f(x)=1 for all values of x, then f(x)=f(x)^2 but f(x) does not equal 0. Does that make sense? We have no function so we can't assume that f(0)=0. f(0) could equal some other value depending on the function.

Kudos [?]: 11 [0], given: 0

Director
Joined: 14 Jan 2007
Posts: 775

Kudos [?]: 179 [0], given: 0

### Show Tags

22 Jul 2007, 09:31
No numerical value of f(x) can be derived from the question. Stem states the values of function in terms of function.

Kudos [?]: 179 [0], given: 0

Senior Manager
Joined: 28 Jun 2007
Posts: 453

Kudos [?]: 8 [0], given: 0

### Show Tags

22 Jul 2007, 12:01
Yeah... consider an example:

f(x) = x+1

f(0) != 0.

f(0) = 1.

Though its not one of those examples that satisfies your equation, I guess it proves that the assumption of f(0)=0 is wrong if there is a constant in the equation.

Kudos [?]: 8 [0], given: 0

22 Jul 2007, 12:01
Display posts from previous: Sort by

# unsolved challenge problem

Moderator: chetan2u

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.