Question

If f (1) = 7 and f (n) = 4 f (n - 1) then find the value of f (5)

Answer 1

1792

Explanation:

given,

f (n) = 4 f (n - 1)

here,

f(2) = 4 f ( 2-1)

= 4 f ( 1 )

= 4. 7

= 28

then,

f(3) = 4 f ( 3-1)

= 4 f ( 2)

= 4. 28

= 112

again,

f (4) = 4 f ( 4-1)

= 4 f ( 3)

= 4.112

=448

at last,

f ( 5) = 4 f ( 5-1)

= 4 f ( 4)

= 4. 448

= 1792