Question
Quantitative Aptitude Question on Functions
If f(ab) = f(a)f(b) for all positive integers a and b, then the largest possible value of f(l) is
A
1
B
3
C
5
D
4
Answer
1
Explanation
Solution
f (1 × 1) = f (1) f (1) Let f (1) = x
∴ x = x2 i.e., x = 0 or 1. The 'largest' value is1.
Alternately, the function which satisfies the condition is an exponential function of the form f(a) = ax .When x = 1, the largest value of f (1) is 1x, which is 1.
Ans: (1)