7. If f is a function satisfying f (x +y) = f(x) f(y) for all x, y N such that f(1) = 3 and
, find the value of n.
Given : f (x +y) = f(x) f(y) for all x, y N such that f(1) = 3
Taking , we have
is forms a GP with first term=3 and common ratio = 3.
Therefore,
Thus, value of n is 4.