GMAT Question of the Day - Daily to your Mailbox; hard ones only

 It is currently 20 Aug 2018, 13:59

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

Function

Author Message
Manager
Joined: 12 Feb 2008
Posts: 175

Show Tags

23 Sep 2008, 07:10

Function $$f(x)$$ satisfies $$f(x) = f(x^2)$$ for all $$x$$ . Which of the following must be true?

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

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.
Current Student
Joined: 28 Dec 2004
Posts: 3280
Location: New York City
Schools: Wharton'11 HBS'12

Show Tags

23 Sep 2008, 07:21
if f(x)=f(x^2) then f(-2)=f(4)...if f(4) then assume if x=4 then f(4)=f(4^2) i.e f(16)..

I will go with B..
Manager
Joined: 22 Jul 2008
Posts: 139

Show Tags

23 Sep 2008, 08:13
f(-2) = f(4) = f(16)
Hence, f(-2) = f(16)
f(16) - f(-2) = 0
Ans. is B
Manager
Joined: 12 Feb 2008
Posts: 175

Show Tags

24 Sep 2008, 05:28
KASSALMD wrote:
f(-2) = f(4) = f(16)
Hence, f(-2) = f(16)
f(16) - f(-2) = 0
Ans. is B

Why do you square twice.

f(-2)=f(4) and thats it.
where does f(16) come from. i understand that f(4)=f(16) but the question says only that f(x)=f(x^2)...........
VP
Joined: 17 Jun 2008
Posts: 1474

Show Tags

25 Sep 2008, 12:41
elmagnifico wrote:
KASSALMD wrote:
f(-2) = f(4) = f(16)
Hence, f(-2) = f(16)
f(16) - f(-2) = 0
Ans. is B

Why do you square twice.

f(-2)=f(4) and thats it.
where does f(16) come from. i understand that f(4)=f(16) but the question says only that f(x)=f(x^2)...........

What f(x) = f(x^2) means that f(2) = f(4) = f(16) = f(256) = ........

Hence, one can use f(16) in place of f(4).

--== Message from GMAT Club Team ==--

This is not a quality discussion. It has been retired.

If you would like to discuss this question please re-post it in the respective forum. Thank you!

To review the GMAT Club's Forums Posting Guidelines, please follow these links: Quantitative | Verbal Please note - we may remove posts that do not follow our posting guidelines. Thank you.
Re: Function &nbs [#permalink] 25 Sep 2008, 12:41
Display posts from previous: Sort by

Function

Moderator: chetan2u

Events & Promotions

 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®.