Give a proof by contraposition of the following statement. If x is an integer and square of x is even, then x is even.

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**Mathematical Propositions and Proofs**

**Topic: Proof by Contraposition**

**The Statement:**
"Give a proof by contraposition of the following statement."

- **If \( x \) is an integer and the square of \( x \) is even, then \( x \) is even.**

**Concept Overview:**
In mathematics, a proof by contraposition is a powerful technique used to prove statements of the form "If \( P \), then \( Q \)." Instead of proving this directly, we can equivalently prove the contrapositive statement: "If not \( Q \), then not \( P \)."

**Application to the Given Statement:**

**Original Statement:** 
If \( x \) is an integer and the square of \( x \) is even, then \( x \) is even.

**Contrapositive Statement:** 
If \( x \) is not even (i.e., \( x \) is odd), then the square of \( x \) is not even (i.e., the square of \( x \) is odd).

**Proof by Contraposition:**

1. **Start with the assumption that \( x \) is odd.**
   - An integer \( x \) is odd if it can be written in the form: \( x = 2k + 1 \), where \( k \) is an integer.

2. **Square both sides to find the square of \( x \):**
   - \( x^2 = (2k + 1)^2 \)
   - \( x^2 = 4k^2 + 4k + 1 \)
   - \( x^2 = 2(2k^2 + 2k) + 1 \)

3. **Analyze the resulting expression:**
   - The expression \( 2(2k^2 + 2k) \) is clearly even since it is multiplied by 2.
   - Adding 1 to an even number yields an odd number.

4. **Conclude that the square of \( x \) is odd:**
   - Therefore, \( x^2 \) is odd when \( x \) is odd.

By proving the contrapositive statement, we have effectively proven the original statement: If \( x \) is an integer and the square of \( x \) is even, then \( x \) is even.

This concludes the
Transcribed Image Text:**Mathematical Propositions and Proofs** **Topic: Proof by Contraposition** **The Statement:** "Give a proof by contraposition of the following statement." - **If \( x \) is an integer and the square of \( x \) is even, then \( x \) is even.** **Concept Overview:** In mathematics, a proof by contraposition is a powerful technique used to prove statements of the form "If \( P \), then \( Q \)." Instead of proving this directly, we can equivalently prove the contrapositive statement: "If not \( Q \), then not \( P \)." **Application to the Given Statement:** **Original Statement:** If \( x \) is an integer and the square of \( x \) is even, then \( x \) is even. **Contrapositive Statement:** If \( x \) is not even (i.e., \( x \) is odd), then the square of \( x \) is not even (i.e., the square of \( x \) is odd). **Proof by Contraposition:** 1. **Start with the assumption that \( x \) is odd.** - An integer \( x \) is odd if it can be written in the form: \( x = 2k + 1 \), where \( k \) is an integer. 2. **Square both sides to find the square of \( x \):** - \( x^2 = (2k + 1)^2 \) - \( x^2 = 4k^2 + 4k + 1 \) - \( x^2 = 2(2k^2 + 2k) + 1 \) 3. **Analyze the resulting expression:** - The expression \( 2(2k^2 + 2k) \) is clearly even since it is multiplied by 2. - Adding 1 to an even number yields an odd number. 4. **Conclude that the square of \( x \) is odd:** - Therefore, \( x^2 \) is odd when \( x \) is odd. By proving the contrapositive statement, we have effectively proven the original statement: If \( x \) is an integer and the square of \( x \) is even, then \( x \) is even. This concludes the
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