a sequence {An}is defined A(1)=0&A(n+1)=A(n)+2(n)WHAT IS VALUE OF A(100)(a)9902(B)9900(C)10100(D)9904

• A(100)= A(99)+2(99)
  A(100)= A(98)+ 2(98)+2(99)
  A(100)= A(97)+2(97)+2(98)+2(99)
  ||LY
  A(100)= A(1)+ 2(1+2+3+4+.......97+98+99)
  
  NOW; 1+2+3.......+97+98+99= 99(2+98)/2= 4950
  (SUM OF AN A.P)
  
  A(100)= 0+ 2(4950)= 9900
• 12 years agoHelpfull: Yes(22) No(5)
• The answer is a.9902.first the data is incorrect in question.A(1)=2 will be the correct data.
  Now
  A(100)=we can write A(99+1) as A(n+1) is given so i broke it in n+1 form.
  then A(99+1)=A(99)+2*99;
  in this way A(99)=A(98)+2*99*98
  in this way..
  ..
  last will be A(1)+2*99*98*.....1
  now put the value 1+2(1+2+......+99)
  2+ 2*99(99+1)/2
  =9902
  
  
• 12 years agoHelpfull: Yes(11) No(15)
• hey tanaya: The que. is correct.. ans would be 9900 if A(1) is 0 as mentioned in the question.
• 12 years agoHelpfull: Yes(7) No(3)
• ans is 9900.
  
• 12 years agoHelpfull: Yes(3) No(1)
• tanaya i get it half ,i don't no how u write 1+2(1+2+............+99)
  
• 12 years agoHelpfull: Yes(1) No(1)
• @tanaya konar
  last will be A(1)+2*99*98*.....1
  now put the value 1+2(1+2+......+99)
  2+ 2*99(99+1)/2
  =9902
  can u explain these steps more clearly plz
• 12 years agoHelpfull: Yes(0) No(5)