Maths Olympiad Prep

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Algebra Difficulty 2.8 Junior Find the answer

Given that the domain of the function f(x)f(x) is (1,3)(1,3), determine the domain of the function f(2x1)f(2x-1).

A) (1,2)(1,2)
B) (1,3)(1,3)
C) (1,5)(1,5)
D) (1,4)(1,4)

Multiple choice: answer with the letter of the option you want.

Solution

Analysis

This problem involves finding the domain of a composite function. We can determine the domain by solving the inequality 1<2x1<31 < 2x - 1 < 3.

Step-by-Step Solution

Step 1: Given that the domain of f(x)f(x) is (1,3)(1, 3), we want to find the domain of f(2x1)f(2x - 1).

Step 2: For f(2x1)f(2x - 1) to have meaning, we must ensure that the input (2x12x - 1) is within the domain of f(x)f(x). In other words, we need to satisfy the inequality 1<2x1<31 < 2x - 1 < 3.

Step 3: Solve the inequality:

1<2x1<31 < 2x - 1 < 3

Add 1 to all parts of the inequality:

2<2x<42 < 2x < 4

Divide all parts of the inequality by 2:

1<x<21 < x < 2

Step 4: Thus, the domain of f(2x1)f(2x - 1) is (1,2)(1, 2).

Therefore, the correct answer is (1,2)\boxed{(1, 2)}.

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Source: NuminaMath-1.5, licensed Apache-2.0. Statement and solution reproduced as published; topic and difficulty added by this site.