BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

Square root of squares ...

This topic has expert replies
Post new topic Post Reply
Previous Topic Next Topic
Junior | Next Rank: 30 Posts
Posts: 16
Joined: Fri Mar 28, 2008 6:01 am
Thanked: 1 times

Square root of squares ...

by richs_ca » Sun May 04, 2008 10:27 am
If X<0 then sq rt of -X \x\ is (note: \x\ is absolute value of x, not sure how to make the propoer symbol.)

I thought the answer was X. X is negative and it asks for the sq rt of -X, so -(-X) is X. And X times the absolute value of X is X*X which is X^2, and the sq rt of that is X.

But it tells me that the answer is -X. What am I missing?
Top
Source: — Problem Solving |
User avatar
GMAT Instructor
Posts: 3225
Joined: Tue Jan 08, 2008 2:40 pm
Location: Toronto
Thanked: 1710 times
Followed by:614 members
GMAT Score:800

Re: Square root of squares ...

by Stuart@KaplanGMAT » Sun May 04, 2008 5:36 pm
richs_ca wrote:If X<0 then sq rt of -X \x\ is (note: \x\ is absolute value of x, not sure how to make the propoer symbol.)

I thought the answer was X. X is negative and it asks for the sq rt of -X, so -(-X) is X. And X times the absolute value of X is X*X which is X^2, and the sq rt of that is X.

But it tells me that the answer is -X. What am I missing?
X is negative and sqrtX is defined as the postive root of X.

So, since the correct answer is positive, and X is negative, we need to multiply X by -1 to make it positive.

In other words, -1(x) = positive number
Image

Stuart Kovinsky | Kaplan GMAT Faculty | Toronto

Kaplan Exclusive: The Official Test Day Experience | Ready to Take a Free Practice Test? | Kaplan/Beat the GMAT Member Discount
BTG100 for $100 off a full course
Top
Newbie | Next Rank: 10 Posts
Posts: 4
Joined: Sun Nov 15, 2009 5:47 pm

by CarpeDiem2011 » Thu Dec 03, 2009 12:35 pm
This question still doesn't make sense - can someone help?
Top
Newbie | Next Rank: 10 Posts
Posts: 5
Joined: Fri Jul 17, 2009 9:39 am

by rohit.reddy » Thu Dec 03, 2009 11:47 pm
according to me the answer should be "i|x|"
Top
User avatar
Junior | Next Rank: 30 Posts
Posts: 11
Joined: Mon Dec 27, 2010 7:31 pm
Thanked: 1 times

by beastly B » Mon Dec 27, 2010 9:11 pm
Stuart Kovinsky wrote:
richs_ca wrote:If X<0 then sq rt of -X \x\ is (note: \x\ is absolute value of x, not sure how to make the propoer symbol.)

I thought the answer was X. X is negative and it asks for the sq rt of -X, so -(-X) is X. And X times the absolute value of X is X*X which is X^2, and the sq rt of that is X.

But it tells me that the answer is -X. What am I missing?
X is negative and sqrtX is defined as the postive root of X.

So, since the correct answer is positive, and X is negative, we need to multiply X by -1 to make it positive.

In other words, -1(x) = positive number
yes x would have to -
Top
User avatar
GMAT Instructor
Posts: 1449
Joined: Sat Oct 09, 2010 2:16 pm
Thanked: 59 times
Followed by:33 members

by fskilnik@GMATH » Tue Dec 28, 2010 5:29 am
Hi there!

I´ve explained all this before, with FULL details/analysis.

Please have a look at the link below.

Regards,
Fabio.

Link: https://www.beatthegmat.com/ds-t71728.html#324807
Fabio Skilnik :: GMATH method creator ( Math for the GMAT)
English-speakers :: https://www.gmath.net
Portuguese-speakers :: https://www.gmath.com.br
Top
Post new topic Post Reply
• Page 1 of 1