Math 20-2

Chapter 1 Inductive and Deductive Reasoning

Lesson 1.4  Proving Conjectures:  Deductive Reasoning

GOAL

The goal of this lesson is stated at the top of page 27 in your textbook, and is also written below.
Keep this in mind as you work through the lesson material.

Prove mathematical statements using a logical argument

Explore...

Try to answer the question in the sidebar on page 27.

Watch

Video Tutorial

Learn About the Math

Information and Examples that present the ideas of this lesson

TEXT Pages 27 - 28

Read/Work through the Learn About the Math section on Pages 27-28 in your textbook.

Go through this material,  AS BEST YOU CAN,  before you view the video tutorials that follow.

Example 1 Connecting conjectures with reasoning

Video Tutorial

Apply the Math

Examples will give you TOOLS for solving problems, and also show you that there may be different ways to approach a question.

YOUR TURN gives YOU the chance to try to do a problem ON YOUR OWN,  using the examples as models.

Example 2  Using deductive reasoning to generalize a conjecture

TEXT Page 28

Work through Example 2 on Page 28  in your textbook.

Watch

Video Tutorial

Your Turn   (I didn’t do a video here)

Example 3  Use deductive reasoning to make a valid conclusion

TEXT Page 29

Work through Example 3 on Page 29 in your textbook.

Watch

Video Tutorial

Your Turn

Use the Video Tutorial for help, or to check your work, BUT... you should do your best to do this question ON YOUR OWN FIRST!

Video Tutorial

Example 4  Using deductive reasoning to prove a geometric conjecture

TEXT Page 29

Work through Example 4 on Page 29 in your textbook.

Watch

Video Tutorial

Your Turn

Use the Video Tutorial for help, or to check your work, BUT... you should do your best to do this question ON YOUR OWN FIRST!

Video Tutorial

Example 5  Communicating reasoning about a divisibility rule

TEXT Page 30

Work through Example 5 on Page 30 in your textbook.

The following demonstration is what I used in my video tutorial.
You can use this to visually check out the conjecture.

Watch

Video Tutorial

Your Turn

Use the Video Tutorial for help, or to check your work, BUT... you should do your best to do this question ON YOUR OWN FIRST!

Video Tutorial

In Summary

Key Ideas and Need to Know 
Presents and summarizes  the main new concepts of the lesson

•	Carefully read through each of the bullet points in this section.

•	If you are unclear about any of these ideas,  ASK YOUR TEACHER FOR HELP!

Practice Problems

Doing Practice Problems

Practice problems reinforce the math presented in this lesson.

•	Work through the practice problems for this lesson.
	These problems are for practice, you don’t need to hand them in!
	(your teacher may assign specific questions for you to complete)

•	Use the answers in the back of the book to CHECK YOUR WORK!

•	If you make a mistake, TRY TO FIX IT!

•	If you need help or want more information, view the video solutions provided.

•	If you still need more help,  CONTACT YOUR TEACHER!

Types of Practice Problems

Check Your Understanding questions require basic understanding of the ideas of the  lesson.

Practising questions will require you to dig deeper for a solution.

Closing  A summary question that often asks YOU to explain ideas in your own words.

Extending questions offer enrichment and extension.

Notes

Question 17,    I didn’t do a video for this one.
I think it’s obvious that using deductive reasoning is a proof,  so Jamie has the best answer.

Question 18,    I didn’t do a video for this one.
A great question, but well beyond the scope of this course!
I wouldn’t have been able to (easily) do it without the answer.
The answer provides some good help here if you tackle this question.

Question 20,    I didn’t do a video for this one.
The answer to this one is contained in the solution for Question 19

Video Solution Links

Check your work for every problem you do!
If you make a mistake,  try to fix it!
Use the video solutions for more information.
If a problem still doesn’t make sense, ASK YOUR TEACHER FOR HELP!

({{"Question 1", "Question 2", "Question 3", "Question 4", "Question 5"}, {"Question 6", "Question 7", "Question 8", "Question 9", "Question 10"}, {"Question 11", "Question 12", "Question 13", "Question 14", "Question 15"}, {"Question 16",  ,  , "Question 19",  }})