Question

anyone know how to help me? O_o
f(1) = 2 and f(2) = 4, f(n) = f(1) + f(2) + f(n - 1), for n > 2
f(5) = ______

Answer 1

Hello @PIRATE..LORD,This is INeedHelpPlease assisting you today!
You have to find f(5)
And given that,
\[f(n) = f(1) + f(2) + f(n - 1)\]
Put n=5
\[f(5)=f(1)+f(2)+f(5-1)\]
f(1) = 2 and f(2) = 4,
Substitute the values,
\(\LARGE f(5)=2+4+f(4)\)-------Let it be equation number 1

Now we need f(4)
Again use,
\[f(n) = f(1) + f(2) + f(n - 1)\]
f(4)=f(1)+f(2)+f(3)
\(\LARGE f(4)=2+4+f(3)\)-----------Let it be equation number 2

Now we need f(3)
Again and again use,
\[f(n) = f(1) + f(2) + f(n - 1)\]
\[\LARGE f(3)=f(1)+f(2)+f(2)\]
f(3)=2+4+4
f(3)=10

Now that we have f(3)'s value,put it in equation number 2
It will reduce to,f(4)=6+f(3)=6+10=16

Now that we have f(4)'s value,put it in equation number 1
It will reduce to,
\[\Huge f(5)=6+f(4)=6+16=22\].

That is your final answer!