if A1=2,A(n+1)=An+2n,
A100=?

• A(n+1)=A(n)+2n
  =>2n=A(n+1)-A(n)
  =>2*1= A(2)-A(1)
  =>2*2= A(3)-A(2)
  =>2*3= A(4)-A(3)
  =>2*4= A(5)-A(4)
  =>2*5= A(6)-A(5)
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  =>2*98=A(99)-A(98)
  =>2*99=A(100)-A(99)
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  Summing up all the above terms we get,
  2*(1+2+....+99) =A(100)-A(1)
  =>A(100)={2*(1+99)*99}/2 + A(1)
  =>A(100)=9900+2
  =>A(100)=9902
  
  Answer A(100)=9902
• 11 years agoHelpfull: Yes(48) No(0)
• it forms g.p
  so 100th term of gp =ar^(n-1)
  first term =2
  ratio=2
  n=100
  =2*2^(100-1)
  =2^100
  so a100 =2^100
• 11 years agoHelpfull: Yes(2) No(16)
• MR. SDEEP, while suming all the terms using 2*(1+2+....+99) =A(100)-A(1), y hv u subtracted A1 ? from A(100) ? IN LHS.
• 11 years agoHelpfull: Yes(1) No(2)
• when u try to solve the question ull notice tht the solution comes in form of ap
  = 2*(99+98+97+96+95......1) +A(1)
  =9902
• 11 years agoHelpfull: Yes(0) No(3)