It is currently 22 Oct 2017, 00:12

### 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 0, what is the value of sq. root (x^u/x^v) ?

Author Message
TAGS:

### Hide Tags

Manager
Joined: 05 Mar 2010
Posts: 202

Kudos [?]: 38 [0], given: 8

If x 0, what is the value of sq. root (x^u/x^v) ? [#permalink]

### Show Tags

11 Jun 2010, 09:32
00:00

Difficulty:

15% (low)

Question Stats:

78% (00:43) correct 22% (01:04) wrong based on 90 sessions

### HideShow timer Statistics

If x ≠ 0, what is the value of sq. root (x^u/x^v) ?

(1) u = v
(2) x is a perfect square.
[Reveal] Spoiler: OA

_________________

Success is my Destiny

Kudos [?]: 38 [0], given: 8

Manager
Joined: 02 May 2010
Posts: 57

Kudos [?]: 44 [0], given: 3

Schools: IU, UT Dallas, Univ of Georgia, Univ of Arkansas, Miami University
WE 1: 5.5 Yrs IT

### Show Tags

11 Jun 2010, 09:59
IMO E

A is INSUFFICIENT.
Equation becomes sqrt (x^(u-v)). If u-v = 0, then the value of the equation is +1 or -1.

B is INSUFFICIENT. We only know that x is a perfect square. Also, we know nothing about u & v.

A and B together dont provide us with any new information.

Kudos [?]: 44 [0], given: 3

Math Expert
Joined: 02 Sep 2009
Posts: 41888

Kudos [?]: 129207 [0], given: 12196

### Show Tags

11 Jun 2010, 10:46
hardnstrong wrote:
If x ≠ 0, what is the value of sq. root (x^u/x^v) ?
(1) u = v
(2) x is a perfect square.

OA will be posted later

$$\sqrt{\frac{x^u}{x^v}}=?$$

(1) $$u=v$$ --> $$\sqrt{\frac{x^u}{x^v}}=\sqrt{\frac{x^u}{x^u}}=\sqrt{1}=1$$. Sufficient.

(2) x is a perfect square --> Clearly not sufficient.

_________________

Kudos [?]: 129207 [0], given: 12196

Manager
Joined: 05 Mar 2010
Posts: 202

Kudos [?]: 38 [0], given: 8

### Show Tags

11 Jun 2010, 21:41
Bunuel wrote:
hardnstrong wrote:
If x ≠ 0, what is the value of sq. root (x^u/x^v) ?
(1) u = v
(2) x is a perfect square.

OA will be posted later

$$\sqrt{\frac{x^u}{x^v}}=?$$

(1) $$u=v$$ --> $$\sqrt{\frac{x^u}{x^v}}=\sqrt{\frac{x^u}{x^u}}=\sqrt{1}=1$$. Sufficient.

(2) x is a perfect square --> Clearly not sufficient.

my question is sq. root of 1 can be +1 or -1 (like sq, root of 4 can be +2 or -2)
How can it be only 1?

OA is A
_________________

Success is my Destiny

Kudos [?]: 38 [0], given: 8

Math Expert
Joined: 02 Sep 2009
Posts: 41888

Kudos [?]: 129207 [0], given: 12196

### Show Tags

12 Jun 2010, 04:33
hardnstrong wrote:
Bunuel wrote:
hardnstrong wrote:
If x ≠ 0, what is the value of sq. root (x^u/x^v) ?
(1) u = v
(2) x is a perfect square.

OA will be posted later

$$\sqrt{\frac{x^u}{x^v}}=?$$

(1) $$u=v$$ --> $$\sqrt{\frac{x^u}{x^v}}=\sqrt{\frac{x^u}{x^u}}=\sqrt{1}=1$$. Sufficient.

(2) x is a perfect square --> Clearly not sufficient.

my question is sq. root of 1 can be +1 or -1 (like sq, root of 4 can be +2 or -2)
How can it be only 1?

OA is A

Square root function can not give negative result.

Any nonnegative real number has a unique non-negative square root called the principal square root and unless otherwise specified, the square root is generally taken to mean the principal square root.

When the GMAT provides the square root sign for an even root, such as $$\sqrt{x}$$ or $$\sqrt[4]{x}$$, then the only accepted answer is the positive root.

That is, $$\sqrt{25}=5$$, NOT +5 or -5. In contrast, the equation $$x^2=25$$ has TWO solutions, +5 and -5. Even roots have only non-negative value on the GMAT.

Odd roots will have the same sign as the base of the root. For example, $$\sqrt[3]{125} =5$$ and $$\sqrt[3]{-64} =-4$$.

Hope it helps.
_________________

Kudos [?]: 129207 [0], given: 12196

Manager
Joined: 05 Mar 2010
Posts: 202

Kudos [?]: 38 [0], given: 8

### Show Tags

12 Jun 2010, 22:18
Didnt know that
Thanks for the precious info.
_________________

Success is my Destiny

Kudos [?]: 38 [0], given: 8

Re: problem   [#permalink] 12 Jun 2010, 22:18
Display posts from previous: Sort by