Live GMAT classes with Target Test Prep start Nov 21 and Nov 22. First class free.

See classes
Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

Newsweek Readers’ Choice Awards 2026 winner: Target Test Prep, #1 Test Prep

Target Test Prep was voted #1 Best Test Prep in the 2026 Newsweek Readers’ Choice™ Awards.

★★★★★5.0563 reviews
GMATLiveTeachStarts Nov 22
Josh Braslow, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Josh Braslow, 20+ years in test prep

Nov 22 · Josh Braslow
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes + 6 months of TTP OnDemand
  • Attend the first class for free
  • Every class is recorded, so you never fall behind
View classes & enroll
Limited seats availableTarget Test Prep
EALiveTeachOnDemandStart anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

EXECUTIVE ASSESSMENT

with

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget Test Prep
GMATOnDemandStart anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions

gmat prep square root and modulus

Expert replies

by rahulsaxena8 » Sun Aug 08, 2010 8:43 pm
commonsense27 wrote:sqrt(x^2)/x=((x^2)^1/2)/x =x^1-1=x^0=1

It does not matter what is value of x is. Answer is 1. If book is saying otherwise, then book needs to be corrected.

BTW, What is the source of this problem?
Hi,

Source is GMAT Prep.

I hope i don't get a similar question in GMAT. As after seeing this approach i m back "to square 1" , pun is totally intended.
Join the discussion

by selango » Sun Aug 08, 2010 9:38 pm
commonsense27 wrote:sqrt(x^2)/x=((x^2)^1/2)/x =x^1-1=x^0=1

It does not matter what is value of x is. Answer is 1. If book is saying otherwise, then book needs to be corrected.

BTW, What is the source of this problem?
sqrt(x^2)/x=((x^2)^1/2)/x

((x^2)^1/2)/x

Let say x=3

Now there are 2 solutions for this.

((3^3)^1/2)/3=(9)^1/2/3

(9)^1/2/3 can be expressed in 2 ways,

((3^2)1/2)/3 or (((-3)^2)1/2)/3

1 or -1
--Anand--
Join the discussion

by sanju09 » Sun Aug 08, 2010 11:01 pm
rahulsaxena8 wrote:Image
[/img]
The value x^2 is always positive, if x ≠ 0. And a positive number inside √ is taken as positive only. The value x could be either positive or negative, so the positivity constraint forces us to take √x^2 as |x| only. The answer to this question is -1, if x < 0; and it is 1, if x > 0. Henceforth, two answers are possible, and [spoiler]E[/spoiler] covers both.
The mind is everything. What you think you become. –Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com
Join the discussion

by selango » Sun Aug 08, 2010 11:08 pm
Thanks Sanju.

Rahul,

Sorry I created a lot of confusion here.

The important point to be noted is sqrt(x^2) is always positive whatever the sign of x.

If x=6,sqrt(36)/6=6/6=1

If x=-6,sqrt(36)/-6=6/-6=-1
Last edited by selango on Sun Aug 08, 2010 11:12 pm, edited 1 time in total.
--Anand--
Join the discussion

by sanju09 » Sun Aug 08, 2010 11:11 pm
selango wrote:Thanks Sanju.

Rahul,

Sorry I created a lot of confusion here.

The important point to be noted is sqrt(x^2) is always positive whatever the sign of x.

If x=6,sqrt(36)=6/6=1

If x=-6,sqrt(36)/-6=6/-6=-1
now what is this in bold?
The mind is everything. What you think you become. –Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com
Join the discussion

by rahulsaxena8 » Sun Aug 08, 2010 11:47 pm
selango wrote:Thanks Sanju.

Rahul,

Sorry I created a lot of confusion here.

The important point to be noted is sqrt(x^2) is always positive whatever the sign of x.

If x=6,sqrt(36)/6=6/6=1

If x=-6,sqrt(36)/-6=6/-6=-1
Anyways I am glad there are people who actively contribute. I was having tough time understanding why my answer was wrong.

Thanks a lot to everyone who contributed.
Join the discussion

by sanju09 » Mon Aug 09, 2010 12:26 am
rahulsaxena8 wrote:
selango wrote:Thanks Sanju.

Rahul,

Sorry I created a lot of confusion here.

The important point to be noted is sqrt(x^2) is always positive whatever the sign of x.

If x=6,sqrt(36)/6=6/6=1

If x=-6,sqrt(36)/-6=6/-6=-1
Anyways I am glad there are people who actively contribute. I was having tough time understanding why my answer was wrong.

Thanks a lot to everyone who contributed.
Thank you the thanks’ stockpile. I can count 4 from you in this single thread so far. Interesting to see Rahul Lakhani not getting one from you.
The mind is everything. What you think you become. –Lord Buddha



Sanjeev K Saxena
Quantitative Instructor
The Princeton Review - Manya Abroad
Lucknow-226001

www.manyagroup.com
Join the discussion

by commonsense27 » Mon Aug 09, 2010 8:27 am
I still stand by my answer. If book is saying otherwise, book needs to be corrected.

We should use our fundamentals to arrive at a choice. If everytime we change our fundamentals based on the question, we will be in deep shit.

This is an exponential problem. There is absolutely nothing wrong that I am doing.
Square root cancels the square. And
X^0=1 as long as the x !=0.

ANSWER IS 1.
Join the discussion

by Ian Stewart » Mon Aug 09, 2010 11:36 am
commonsense27 wrote:I still stand by my answer. If book is saying otherwise, book needs to be corrected.

We should use our fundamentals to arrive at a choice. If everytime we change our fundamentals based on the question, we will be in deep shit.

This is an exponential problem. There is absolutely nothing wrong that I am doing.
Square root cancels the square. And
X^0=1 as long as the x !=0.

ANSWER IS 1.
No, sqrt(x^2) is *not* always equal to x. You can see this by plugging in x = -2, say. Then sqrt(x^2) = sqrt(4) = 2, which is not equal to x; it's equal to -x. In general, sqrt(x^2) is *always* equal to |x|, but it is only equal to x if x is zero or greater.

When learning a mathematical rule, it's important to learn when you are allowed to apply it, and when you are not. The rule you are trying to use here, that (x^a)^b = x^(ab), is *not* always true if x is negative. If you don't want to take my word for it, you can read the 'Real powers of positive numbers' section here:

en.wikipedia.org/wiki/Exponentiation#Identities_and_properties

The GMAT does this all the time - tests if you understand the exceptions to the familiar algebraic rules you have learned. Often it's just as important to know when you *can't* apply a rule as it is to know when you can.
For online GMAT math tutoring, or to buy my higher-level Quant books and problem sets, contact me at ianstewartgmat at gmail.com

ianstewartgmat.com
Join the discussion