CAT Quantitative Aptitude Questions | CAT Algebra - Functions questions

This is an Unconventional Question. It is about a function which is a multiplication of two other functions. Functions is a simple topic which involves a lot of basic ideas. Make sure that you a get of hold of them by solving these questions. A range of CAT questions can be asked based on this simple concept of Functions questions in the CAT Exam. Make sure you practice a lot of questions in CAT Functions Algebra to push your CAT preparation in the right direction. Functions as an idea is a fabulous idea if one can wrap their head around it the right way, and it has been one of the staple ideas tested by the CAT exam historically.

Question 7: f(x + y) = f(x)f(y) for all x, y, f(4) = + 3 what is f(–8)?

1. \\frac{1}{3}\\)
2. \\frac{1}{9}\\)
3. 9
4. 6

Video Explanation

Explanatory Answer

Method of solving this CAT Question from CAT Algebra - Functions: How do we write -8 as x + y ?

f(x + 0) = f(x) f(0)
f(0) = 1
f(4 + – 4) = f(0)
f(4 + – 4) = f(4) f(–4)
1 = +3 * f(–4)
f(-4) = \\frac{1}{3}\\)
f(– 8) = f(– 4 + (– 4)) = f(– 4) f(– 4)
f(– 8) = \\frac{1}{3}\\) * \\frac{1}{3}\\) = \\frac{1}{9}\\)

The question is "f(x + y) = f(x)f(y) for all x, y, f(4) = + 3 what is f(–8)?"

Hence the answer is "\\frac{1}{9}\\)"

Choice B is the correct answer.