The sequence {A(n)} is defined by A(1) = 2 and A(n+1)=A(n)+2*n what is the value of A(100)?

A. 9902
B. 9900
C. 10100
D. 9904

• n=1, A(1)=2
  n=2, A(2)=A(1+1)=A(1)+2*1=2+2=4
  n=3, A(3)=A(2+1)=A(2)+2*2=4+4=8
  n=4, A(4)=A(3+1)=A(3)+2*3=8+6=14
  if n=1, A(1)=2
  if n=2, A(2)=4, i.e 2*2-0=4
  if n=3, A(3)=8, i.e 3*3-1=8
  if n=4, A(4)=14 i.e 4*4-2=14
  ..........
  if n=100, A(100)=100*100-98=10000-98=9902
  ans=9902
  
  .
  
• 9 years agoHelpfull: Yes(18) No(0)
• Solve recurrence relation
  finally
  A(1)+2*(1+2+3...99)
  which is 2+2*99*100/2
  9902ans
• 9 years agoHelpfull: Yes(9) No(0)
• A(1)=2
  so A(2)=A(1)+2*1
  which is 4
  similarly
  A(3)=A(2)+2*2
  4+4=8
  then
  A(4)=A(3)+2*3
  8+6=14
• 9 years agoHelpfull: Yes(1) No(1)