• Placement Papers
• /
• TCS

TCS Question Papers: TCS Interview Experience(90) TCS Company Profile

(#M40012255) TCS question Keep an EYE

what is the value of
1(1!)+2(2!)+3(3!)+.............+2012(2012!)=?

Asked In TCS kesav chari (11 years ago)

Unsolved Read Solution (3)

Is this Puzzle helpful?   (13)   (1) Submit Your Solution

Read Solution (3) :

kesav chari  (11 years ago)

1(1!)+2(2!)=5 ie 3!-1
1(1!)+2(2!)+3(3!)=23 ie 4!-1
1(1!)+2(2!)+3(3!)+.............+2012(2012!)=2013!-1

Is this solution Helpfull? Yes (49) | No   

Sanjeev Sarkar  (11 years ago)

(1!)(1) = 1
(1!)(1) + (2!)(2) = 5
(1!)(1) + (2!)(2) + (3!)(3) = 23
(1!)(1) + (2!)(2) + (3!)(3) + (4!)(4) = 119

Therefore, having noticed a pattern, we conjecture that (1!)(1) + (2!)(2) + ... + (n!)(n) = (n + 1)! - 1

So here n = 2012
thus the sum is (2012 + 1)!-1

= 2013! -1

Is this solution Helpfull? Yes (15) | No   

sanchi chawla  (11 years ago)

i dont get it

Is this solution Helpfull? Yes | No (1)  

Please Login to Read Solution.