Answer: 2n.
- A n
- B n²
- C 2<sup>n</sup>
- D 2n
Correct answer: D. 2n
Explanation: Cauchy's functional equation: set y=1 repeatedly. f(2)=f(1)+f(1)=4, f(3)=f(2)+f(1)=6. By induction, f(n)=n·f(1). With f(1)=2: f(n)=n×2=2n. Answer: f(n) = 2n
Concept context
Ordered pairs, Cartesian products, types of relations and functions, domain and range. Foundation for calculus and Class 12 algebra.