‎1(1!)+2(2!)+3(3!)+....+2010(2010!)+2011(2011!)+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(39) No(1)
• Let n=2012 =>n*n!=(n+1)!-n! =>2!-1!+3!-2!+4!-3!+---------2013!-2012!
  Cancel out the + and neg no. you will get 2013!-1.
• 12 years agoHelpfull: Yes(7) No(0)
• n(n!)=(n+1-1)n!=((n+1)n!-n!)
  =(n+1)!-n!
  =>2!-1!+3!-2!.....2012!-2011!+2013!-2012!=2013!-1
• 12 years agoHelpfull: Yes(7) No(0)
• (2!-1!)+(3!-2!)+(4!-3!)....(2012!-2011!)+(2013!-2012!)
  =2013!-1!
• 12 years agoHelpfull: Yes(2) No(1)