1+1×1! + 2 ×2! …………………………………………………100×100!

• ans is 101! add as first two term 1+1*1!=2! same as now add first three term 1+1*1+2*2!=3! proceed same as so ans is 101!
• 10 years agoHelpfull: Yes(21) No(0)
• sum for 1 term: 1
  sum for 2 terms: 1+1*1!=2=2!
  sum for 3 terms: 1+1*1!+2*2!=6=3!
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  .
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  sum of 101 terms= 101! answer
  (since 100*100! is 101th term)
• 10 years agoHelpfull: Yes(12) No(0)
• 1+1*1!=2*1=2!
  1+1*1!+2*2!=3!
  1+1*1!+2*2!...100*100!=101!
• 10 years agoHelpfull: Yes(4) No(0)
• 1*1!=1 or 2!-1
  1*1!+2*2!=1+4=5 or 3!-1
  
  similarly ......100*100! = 101!-1
• 10 years agoHelpfull: Yes(3) No(3)
• ans is 101!
  1*1!+2*2!+3*3!+......+k*k! = (k+1)!-1
  then
  1*1!+2*2!+..........+100*100!=101!-1
  1+1*1!+2*2!+.........+100*100!=101!
• 10 years agoHelpfull: Yes(2) No(0)
• 1*1!=2!-1=1
  2*2!=4 ,4+1=5 or 3!-1
  +....+100*100!=101!-1
  1+101!-1
  101!
• 10 years agoHelpfull: Yes(1) No(0)
• as we know,n*n!=(n+1)!-n!
  therefore,1+1*1!+2*2!+............100*100! is written as
  =1+(2!-1!)+(3!-2!)+(4!-3!)+.......+(101!-100!)
  =101!
• 10 years agoHelpfull: Yes(1) No(0)
• n*n!= (n+1-1)*n!
  = (n+1)*n! - n!
  = (n+1)! - n!
  
  so according to d que.. 1+2!-1!+3!-2!....+101!-100!
  = 101!
  ans 101!
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• n*(n+1)2
  here n=100
  100*1012
  50*101=5050
  hence the ans is 5050
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• 1*1!+2*2!+3*3!.........+ n*n!=n!
  
  
  1+1*1!+2*2!+.........+100*100!=100!+1
  
  
  
  
• 10 years agoHelpfull: Yes(0) No(0)
• (2-1)*1!+(3-1)*2!+...+(101-1)*100!
  2!-1!+3!-2!+......+101!-100!
  on solving
  101!-1!
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