Intro to Proofs

Page 2: Definitions, Postulates, and Theorems

  • Definitions: Meanings of words used in proofs.

  • Postulates: Basic ideas accepted as truth without proof.

  • Theorems: Ideas that have been proven true multiple times.

Page 4: Conjecture and Proof

  • Conjecture: Propositions that are believed to be true but need verification.

  • Proof Context: To verify conjectures, one must provide a logical argument.

Page 5: Flowchart of a Proof

  • A flowchart represents a systematic approach to constructing a proof with:

    • Conclusions, postulates, definitions, or theorems involved at each step.

    • Reminder: Counterexamples can disprove statements at any point.

Page 6: Paragraph Proofs

  • Historical Context: Euclid’s proofs were initially written in paragraph form.

  • Purpose: To make a precise argument regarding a statement.

Page 7: Structuring 2-Column Proofs

  • Organization:

    • Statements: Listed in numbered steps.

    • Reasons: Use definitions, postulates, and theorems to validate your statements.

Page 8: Importance of Structured Proofs

  • Reasons for Using 2-Column Proofs:

    1. Enhances academic performance.

    2. An organized method for demonstrating validity or falsehood in claims.

Page 9: Example of a 2-Column Proof

  • Given: 2x + 5 = 11

  • Prove: x = 3

    • Steps:

      1. 2x + 5 = 11

      2. 2x = 6

      3. x = 3

    • Reasons:

      1. Given

      2. Subtraction Property

      3. Division Property

Page 10: Conclusions in Proofs

  • Conclusion: The last statement concludes that the conjecture is true if all prior statements and reasons hold true.

Page 13: UNO Postulates

  • Postulates/Rules in Playing UNO:

    • Similar to the proper structuring of proofs, where certain conditions must be adhered to.

Page 15: Subsequent Steps in Proofs

  • Requirement: Similar conditions to be followed in card play to develop further proof statements.

Page 16: Continued Card Play Dynamics

  • Ongoing theme of using card game rules as analogies for proof structuring.

Page 17: Preparing to Write Algebra Proofs

  • Transition: Contextual shift to algebraic proofs and structures.

Page 18: Algebra Proof Method

  • Example: Solve - Given: 2x + 5 = 11, prove x = 3.

    1. 2x + 5 = 11

    2. 2x = 6

    3. x = 3

    • Reasoning includes properties of equality involved.

Page 19: Writing 2-Column Proofs

  • Emphasizes the necessity to construct true statements and corresponding reasons effectively.

Page 20: Starting Statements

  • Initialization: The first statement is always the 'Given'.

Page 21: Developing Your Proof

  • Steps in proof writing must follow a logical flow using appropriate reasoning.

Page 22: Concluding Steps

  • Final Statement: Always end with the prove statement and its corresponding reason.

Page 23: Commonly Used Properties

  • Common Proof Reasons: Lists properties crucial for proof development.

Page 24-25: Explanation of Properties

  • Addition, Subtraction, Multiplication and Division Properties: Explained in terms of their usage in proofs.

Page 26-29: Example Proofs

  • Example proofs illustrating how to structure statements and reasons effectively.

Page 30-36: More Algebraic Proof Examples

  • Multiple examples to develop understanding of various algebraic proofs.

Page 37: Introduction to Geometry Proofs

  • Transition into geometry and proof structures, particularly focusing on transversals.

Page 38-44: Geometry Proof Examples

  • Detailed geometry proofs demonstrating corresponding angles, alternate interior angles, and their logical structuring using established theorems and postulates.