Math Problem Statement

Which value is a counterexample to Molly's conjecture?

Solution

To find a counterexample to Molly's conjecture that x3>3x+3x^3 > 3x + 3 for all x>0x > 0, we need to identify a specific value of x>0x > 0 for which the inequality does not hold.

Let's start by testing some simple values of xx:

  1. For x=1x = 1: x3=13=1x^3 = 1^3 = 1 3x+3=3(1)+3=63x + 3 = 3(1) + 3 = 6 Comparison: 1<6\text{Comparison: } 1 < 6 The inequality x3>3x+3x^3 > 3x + 3 does not hold for x=1x = 1.

Therefore, x=1x = 1 is a counterexample to Molly's conjecture. For x=1x = 1, the inequality 13>3(1)+31^3 > 3(1) + 3 fails because 11 is not greater than 66.

Would you like to explore other counterexamples or have any other questions?

Related Questions:

  1. What is the largest value of xx for which x3<3x+3x^3 < 3x + 3 holds?
  2. What happens to the inequality when x>2x > 2?
  3. Can you identify any intervals where the inequality might hold true?
  4. How does the inequality behave as xx approaches infinity?
  5. Is there a way to modify the conjecture so that it becomes true?

Tip: When identifying counterexamples, start with small integer values—they are often easier to calculate and reveal patterns quickly.

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Math Problem Analysis

Mathematical Concepts

Inequalities

Formulas

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Theorems

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Suitable Grade Level

Grades 9-12