if f(x+y)=f(x)+f(y)+8xy-2 and f(1)=1 then find the value of f(2)+f(3).??

• f(1)=1
  put x=1 & y=1
  f(1+1)=f(1)+f(1)+8-2=8 so f(2)=8
  put x=1 & y=2
  f(1+2)=f(1)+f(2)+16-2=23
  so f(3)=23
  therefore, f(2)+f(3)=8+23=31 (ans)
  
  
• 11 years agoHelpfull: Yes(27) No(0)
• Let x=1, y=1;
  Then (x+y) = 2;
  so f(2) = f(1) + f(1)+8-2
  = 1+ 1+ 8 -2
  =8
  let x=2, y =1;
  then (x+y)= 3
  so f(3) = f(2)+ f(1) + (8*2*1) - 2
  = 8+ 1+16-2
  =23
  so the answer is f(2) + f(3) is (8+23)= 31
• 11 years agoHelpfull: Yes(6) No(1)
• sry made a mistake!submitted the answer of a different question here!the question is If f(f(n))+f(n)=2n+3 and f(0)=1, what is the value of f(2012)?
• 11 years agoHelpfull: Yes(2) No(0)
• ans=31
  ..
  
• 11 years agoHelpfull: Yes(1) No(0)
• Put n = 0
  Then f(f(0))+f(0) = 2(0) + 3 ⇒ f(1) + 1 = 3 ⇒ f(1) = 2
  Put n = 1
  f(f(1)) + f(1) = 2(1) + 3 ⇒ f(2) + 2 = 5 ⇒f(2) = 3
  Put n = 2
  f(f(2)) + f(2) = 2(2) + 3 ⇒ f(3) + 3 = 7 ⇒ f(3) = 4
  ......
  f(2012) = 2013
• 11 years agoHelpfull: Yes(0) No(4)
• f(1+1)=f(2)=f(1)+f(1)+8*1*1-2=2+2+8-2=10
  f(2+1)=f(3)=f(2)+f(1)+8*2*1-2=10+2+16-2=26
  f(2)+f(3)=36
• 11 years agoHelpfull: Yes(0) No(1)
• 31
• 11 years agoHelpfull: Yes(0) No(0)
• Given
  f(1)=1
  so
  put x=1 & y=1
  f(1+1)=f(1)+f(1)+8-2=8 so f(2)=8
  put x=1 & y=2
  f(1+2)=f(1)+f(2)+16-2=23
  so f(3)=23
  therefore, f(2)+f(3)=8+23=31 (ans)
• 11 years agoHelpfull: Yes(0) No(0)