Find all School-related info fast with the new School-Specific MBA Forum

 It is currently 31 May 2016, 20:01

### 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

# if x is an integer, which value of x will yield the largest

Author Message
Current Student
Joined: 28 Dec 2004
Posts: 3385
Location: New York City
Schools: Wharton'11 HBS'12
Followers: 14

Kudos [?]: 227 [0], given: 2

if x is an integer, which value of x will yield the largest [#permalink]

### Show Tags

31 Jul 2008, 10:42
This topic is locked. If you want to discuss this question please re-post it in the respective forum.

if x is an integer, which value of x will yield the largest value for 5^-(x-3)^2

x= 3, -3, 9, -9, 0

Note: I saw something similar to this on my own exam..the numbers are made-up of course, the function is madeup also..just trying to test the concept..
SVP
Joined: 30 Apr 2008
Posts: 1888
Location: Oklahoma City
Schools: Hard Knocks
Followers: 39

Kudos [?]: 526 [0], given: 32

### Show Tags

31 Jul 2008, 10:50
I think the answer would be 3.

regardless of x being greater or less than 3, the - in the front will switch the sign after squaring and make the exponent negative for sure. So we will have $$\frac{1}{5^n}$$ where $$n = (x-3)^2$$

If x = 3, then we have -(3-3)^2, or 0^2 = 0, and -0 = 0, and so we then have $$\frac{1}{5^0} = 1/1 = 1$$.

Every other value listed for x will give an actual power making 5 * 5 * 5 * 5 or whatever that value becomes. With 5 being in the denominator, the largest fraction will be the one with the smallest denominator.

fresinha12 wrote:
if x is an integer, which value of x will yield the largest value for 5^-(x-3)^2

x= 3, -3, 9, -9, 0

Note: I saw something similar to this on my own exam..the numbers are made-up of course, the function is madeup also..just trying to test the concept..

_________________

------------------------------------
J Allen Morris
**I'm pretty sure I'm right, but then again, I'm just a guy with his head up his a$$. GMAT Club Premium Membership - big benefits and savings Director Joined: 12 Jul 2008 Posts: 518 Schools: Wharton Followers: 22 Kudos [?]: 142 [0], given: 0 Re: exponent question [#permalink] ### Show Tags 31 Jul 2008, 10:51 fresinha12 wrote: if x is an integer, which value of x will yield the largest value for 5^-(x-3)^2 x= 3, -3, 9, -9, 0 Note: I saw something similar to this on my own exam..the numbers are made-up of course, the function is madeup also..just trying to test the concept.. If I'm reading this right 5^-(x-3)^2 = 1/(5^(x-3)^2) That means you're trying to minimize 5^(x-3)^2 And from that, you're trying to minimize |x-3| Of the answer choices, 3 would be the best choice. Intern Joined: 28 May 2008 Posts: 7 Followers: 0 Kudos [?]: 0 [0], given: 0 Re: exponent question [#permalink] ### Show Tags 31 Jul 2008, 10:52 I think answer is 3. 5^-(x-3)^2 => 1/5^(x-3)^2 1/5^(x-3)^2 => 3 makes the denominator 1 other values greater than 1. VP Joined: 17 Jun 2008 Posts: 1397 Followers: 8 Kudos [?]: 217 [0], given: 0 Re: exponent question [#permalink] ### Show Tags 31 Jul 2008, 11:01 fresinha12 wrote: if x is an integer, which value of x will yield the largest value for 5^-(x-3)^2 x= 3, -3, 9, -9, 0 Note: I saw something similar to this on my own exam..the numbers are made-up of course, the function is madeup also..just trying to test the concept.. to get the largest value of the function f(x)=5^-(x-3)^2 (x-3)^2 should be minimum.hence x=3 is the correct value _________________ cheers Its Now Or Never SVP Joined: 30 Apr 2008 Posts: 1888 Location: Oklahoma City Schools: Hard Knocks Followers: 39 Kudos [?]: 526 [0], given: 32 Re: exponent question [#permalink] ### Show Tags 31 Jul 2008, 11:01 mbathlagamt08 - Welcome to GMAT club! mbathlagmat08 wrote: I think answer is 3. 5^-(x-3)^2 => 1/5^(x-3)^2 1/5^(x-3)^2 => 3 makes the denominator 1 other values greater than 1. _________________ ------------------------------------ J Allen Morris **I'm pretty sure I'm right, but then again, I'm just a guy with his head up his a$$.

GMAT Club Premium Membership - big benefits and savings

SVP
Joined: 07 Nov 2007
Posts: 1820
Location: New York
Followers: 30

Kudos [?]: 709 [0], given: 5

### Show Tags

31 Jul 2008, 11:28
fresinha12 wrote:
if x is an integer, which value of x will yield the largest value for 5^-(x-3)^2

x= 3, -3, 9, -9, 0

Note: I saw something similar to this on my own exam..the numbers are made-up of course, the function is madeup also..just trying to test the concept..

1) Largest value 5^-(x-3)^2 = when (x-3)^2 is least value..

(x-3) ^2 least value =0 --> when x=3.
_________________

Smiling wins more friends than frowning

Current Student
Joined: 28 Dec 2004
Posts: 3385
Location: New York City
Schools: Wharton'11 HBS'12
Followers: 14

Kudos [?]: 227 [0], given: 2

### Show Tags

31 Jul 2008, 12:02
i agree with my example ans should be 3...

however on the exam..the ans choice listed didnt make (x-N)^2=0..i spent about 2 mins and just guessed..i think i was dubed by gmac..my exam was buggy..
SVP
Joined: 07 Nov 2007
Posts: 1820
Location: New York
Followers: 30

Kudos [?]: 709 [0], given: 5

### Show Tags

31 Jul 2008, 12:07
fresinha12 wrote:
i agree with my example ans should be 3...

however on the exam..the ans choice listed didnt make (x-N)^2=0..i spent about 2 mins and just guessed..i think i was dubed by gmac..my exam was buggy..

(x-N)^2=0 are you sure that power is 2 or -2 power.

(x-n)^-2 in this case.. answer could be different.
_________________

Smiling wins more friends than frowning

Re: exponent question   [#permalink] 31 Jul 2008, 12:07
Display posts from previous: Sort by