Find the value of 1.1! + 2.2! + 3.3! + ......+n.n! 1) n! : PS Archive
Check GMAT Club Decision Tracker for the Latest School Decision Releases http://gmatclub.com/AppTrack

 It is currently 20 Jan 2017, 01:35

### 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

# Events & Promotions

###### Events & Promotions in June
Open Detailed Calendar

# Find the value of 1.1! + 2.2! + 3.3! + ......+n.n! 1) n!

 post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
CEO
Joined: 15 Aug 2003
Posts: 3460
Followers: 67

Kudos [?]: 862 [0], given: 781

Find the value of 1.1! + 2.2! + 3.3! + ......+n.n! 1) n! [#permalink]

### Show Tags

07 Oct 2003, 15:50
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 2 sessions

### HideShow timer Statistics

This topic is locked. If you want to discuss this question please re-post it in the respective forum.

Find the value of 1.1! + 2.2! + 3.3! + ......+n.n!

1) n! +1
2) (n+1)!
3) (n+1)!-1
4) (n+1)!+1

Explain your choice
VP
Joined: 21 Sep 2003
Posts: 1065
Location: USA
Followers: 3

Kudos [?]: 73 [0], given: 0

### Show Tags

07 Oct 2003, 17:33
Let me try...

n.n! = (n+1-1).n! = (n+1).n! - n! = (n+1)! - n!

So the series
1.1! + 2.2! + 3.3! + 4.4! +..............+ n.n!
can be written as :
(2!-1!) + (3! -2!) + (4! - 3!) + ......... + (n+1)! -n!

Cancelling the intermidiate terms we get

-1! + (n+1)! = (n+1)! -1

Ans (3)
07 Oct 2003, 17:33
Display posts from previous: Sort by

# Find the value of 1.1! + 2.2! + 3.3! + ......+n.n! 1) n!

 post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group and phpBB SEO Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.