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

• 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
• 12 years agoHelpfull: Yes(49) No(0)
• (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
• 12 years agoHelpfull: Yes(15) No(0)
• i dont get it
• 12 years agoHelpfull: Yes(0) No(1)