Math Problem Statement

|2x-1|≥|x-1|

Solution

To solve the inequality 2x1x1|2x - 1| \geq |x - 1|, we can approach it by considering the different cases for the absolute values, based on the expressions inside them.

Step 1: Identify critical points

The expressions inside the absolute values, 2x12x - 1 and x1x - 1, become zero when:

  • 2x1=02x - 1 = 0 implies x=12x = \frac{1}{2}
  • x1=0x - 1 = 0 implies x=1x = 1

These points divide the number line into three intervals:

  1. x<12x < \frac{1}{2}
  2. 12x<1\frac{1}{2} \leq x < 1
  3. x1x \geq 1

Step 2: Analyze each interval

Let's consider the behavior of the absolute value expressions in each interval.

Case 1: x<12x < \frac{1}{2}

In this interval:

  • 2x1<02x - 1 < 0, so 2x1=(2x1)=2x+1|2x - 1| = -(2x - 1) = -2x + 1
  • x1<0x - 1 < 0, so x1=(x1)=x+1|x - 1| = -(x - 1) = -x + 1

The inequality becomes: 2x+1x+1-2x + 1 \geq -x + 1 Subtracting 1 from both sides: 2xx-2x \geq -x Adding 2x2x to both sides: 0x0 \geq x

Since x<12x < \frac{1}{2}, this inequality holds for all x0x \leq 0.

Case 2: 12x<1\frac{1}{2} \leq x < 1

In this interval:

  • 2x102x - 1 \geq 0, so 2x1=2x1|2x - 1| = 2x - 1
  • x1<0x - 1 < 0, so x1=x+1|x - 1| = -x + 1

The inequality becomes: 2x1x+12x - 1 \geq -x + 1 Adding xx to both sides: 3x113x - 1 \geq 1 Adding 1 to both sides: 3x23x \geq 2 Dividing by 3: x23x \geq \frac{2}{3}

Since x23x \geq \frac{2}{3} and x<1x < 1, the inequality holds for 23x<1\frac{2}{3} \leq x < 1.

Case 3: x1x \geq 1

In this interval:

  • 2x102x - 1 \geq 0, so 2x1=2x1|2x - 1| = 2x - 1
  • x10x - 1 \geq 0, so x1=x1|x - 1| = x - 1

The inequality becomes: 2x1x12x - 1 \geq x - 1 Subtracting xx from both sides: x0x \geq 0

Since x1x \geq 1, this inequality holds for all x1x \geq 1.

Step 3: Combine the intervals

  • In x0x \leq 0
  • In 23x<1\frac{2}{3} \leq x < 1
  • In x1x \geq 1

Thus, the solution to the inequality 2x1x1|2x - 1| \geq |x - 1| is: x0orx23x \leq 0 \quad \text{or} \quad x \geq \frac{2}{3}

Final Answer: (,0][23,)(-\infty, 0] \cup \left[\frac{2}{3}, \infty\right)

Would you like more details on this solution or have any other questions?

Here are 5 related questions:

  1. How do you solve inequalities involving absolute values?
  2. What happens if you square both sides of an inequality with absolute values?
  3. How do you graph the solution of 2x1x1|2x - 1| \geq |x - 1|?
  4. Can absolute value inequalities have no solution?
  5. How do absolute value inequalities differ from standard inequalities?

Tip: When dealing with absolute value inequalities, always remember to consider the critical points where the expressions inside the absolute values are zero; this helps to break the problem into manageable cases.

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Math Problem Analysis

Mathematical Concepts

Absolute Value
Inequalities
Critical Points
Interval Analysis

Formulas

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Theorems

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Suitable Grade Level

High School