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

It is currently 14 Oct 2019, 06:15

Close

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
Your Progress

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

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Close

Request Expert Reply

Confirm Cancel

What is (-1)^1 + (-1)^2 + ... + (-1)^2006?

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

Find Similar Topics 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 58312
What is (-1)^1 + (-1)^2 + ... + (-1)^2006?  [#permalink]

Show Tags

New post 26 Mar 2019, 05:18
00:00
A
B
C
D
E

Difficulty:

  5% (low)

Question Stats:

83% (00:34) correct 17% (00:39) wrong based on 52 sessions

HideShow timer Statistics

Director
Director
avatar
G
Joined: 22 Nov 2018
Posts: 557
Location: India
GMAT 1: 640 Q45 V35
GMAT 2: 660 Q48 V33
GMAT ToolKit User Premium Member
Re: What is (-1)^1 + (-1)^2 + ... + (-1)^2006?  [#permalink]

Show Tags

New post 26 Mar 2019, 05:27
1
1
If the power of the end term is odd then -1 and if even then 0. As 2006 is even it is option c 0

Posted from my mobile device
_________________
Give +1 kudos if this answer helps..!!
CEO
CEO
User avatar
V
Joined: 12 Sep 2015
Posts: 3990
Location: Canada
Re: What is (-1)^1 + (-1)^2 + ... + (-1)^2006?  [#permalink]

Show Tags

New post 26 Mar 2019, 07:00
Top Contributor
Bunuel wrote:
What is \((-1)^1 + (-1)^2 + ... + (-1)^{2006}\)?

(A) -2006
(B) -1
(C) 0
(D) 1
(E) 2006


In TOTAL, there are 2006 terms to add
The pattern alternates between -1 and 1: (-1) + 1 + (-1) + 1 + (-1) + 1 + . . . . . . (-1) + 1
Every PAIR of consecutive values add to 0
That is, (-1) + 1 = 0

So, (-1) + 1 + (-1) + 1 + (-1) + 1 + . . . . . . (-1) + 1 = 0 + 0 + 0 . . . . + 0 + 0
Since we have an EVEN number of terms (2006 terms), we have exactly 1003 PAIRS (of -1 and 1) that add to 0
So, the sum becomes the sum of 1003 0's, which is ZERO

Answer: C

Cheers,
Brent
_________________
Test confidently with gmatprepnow.com
Image
GMAT Club Legend
GMAT Club Legend
User avatar
D
Joined: 18 Aug 2017
Posts: 4978
Location: India
Concentration: Sustainability, Marketing
GPA: 4
WE: Marketing (Energy and Utilities)
GMAT ToolKit User Premium Member
Re: What is (-1)^1 + (-1)^2 + ... + (-1)^2006?  [#permalink]

Show Tags

New post 26 Mar 2019, 11:13
Bunuel wrote:
What is \((-1)^1 + (-1)^2 + ... + (-1)^{2006}\)?

(A) -2006
(B) -1
(C) 0
(D) 1
(E) 2006


pair of odd & even ; 2006/2 ; 1003
so equal of both sets sum = 0
IMO C
_________________
If you liked my solution then please give Kudos. Kudos encourage active discussions.
GMAT Club Bot
Re: What is (-1)^1 + (-1)^2 + ... + (-1)^2006?   [#permalink] 26 Mar 2019, 11:13
Display posts from previous: Sort by

What is (-1)^1 + (-1)^2 + ... + (-1)^2006?

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  





Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne