f(x+y)=f(x)*f(y)
f(1)=1.6,
If f(1)+f(2)+f(3)+....+f(n) lies between 24 and 27. Find the value of n?

• here it is given that f(x+y)=f(x)*f(y)
  f(1)=1.6
  f(2)=f(1)*f(1)=1.6*1.6
  f(3)=f(2)*f(1)=1.6*1.6*1.6
  similarly for f(4) = 1.6 ^ 4
  thus forming the gp
  sum of gp to n terms is (a(r^n-1))/(r-1)
  here a=1.6 and r=1.6
  (1.6((1.6)^n - 1))/(1.6 - 1) => 2.67((1.6)^n - 1) = for n=5 the value comng is 25.32 ,, thus the value of n=5 ....
• 11 years agoHelpfull: Yes(1) No(0)
• n=5...
  1.6(1+2+3+4+5)=24
  &
  1.6(1+2+3+4+5+6)=33.6
  
  since f(1)=1.6;f(2)=3.2; f(3)=4.8; f(4)=6.4
• 11 years agoHelpfull: Yes(0) No(0)
• f(1)=1.6
  f(2)=f(1)+f(1)=1.6+1.6=3.2
  f(3)=4.8
  f(4)=6.4
  f(5)=8.0
  f(24)=38.4
  f(27)=43.2.
• 11 years agoHelpfull: Yes(0) No(0)