Question

If f(1)=9 and f(n)=f(n-1)+2 then find the value of f(5)

Answer 1

Explanation:

hello :

f(n)=f(n-1)+2

means : f(n)-f(n-1)=2

this is the arithmetic seq when the common dif is d= 2 and the first term is : 9

the n-ieme term is : f(n) = f(1) +(n-1)d

f(n) =9+2(n-1)

f(n) = 2n+7

so : f(5) = 2(5)+7 = 17