CAT 2024 Slot 3 QA Question 15

Multiple choice (+3 / −1) · Algebra · Functions · Try it, then check the answer and solution below.

CAT 2024 Slot 3QAAlgebra • FunctionsModerate
For any non-zero real number x, let f(x)+2f(1x)=3xf(x) + 2 f(\frac{1}{x}) = 3x. Then, the sum of all possible values of xx for which $f(x) = 3 , is
Answer and solution

Answer: D) -3

📌 Core Concept
The problem involves solving a functional equation and finding the sum of roots of a quadratic equation. The key steps involve setting up a system of equations to solve for the function f(x)f(x) and then using the quadratic formula or Vieta's formulas to find the sum of the roots.
🔢 Step-by-Step Solution
1
Given Functional Equation:
f(x)+2f(1x)=3x(1)f(x) + 2 f\left(\frac{1}{x}\right) = 3x \quad \text{(1)}
2
Substitute xx with 1x\frac{1}{x} :
\[ f\left( 1x\frac{1}{x} \right) + 2 f(x) = 3x\frac{3}{x} \quad \text{(2)} \

Keep going

Related Functions questions