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Geometry Ch2.6 #9 #10

Question from John:

Chapter 2, Lesson 6, Number 9 Why does the demonstration not prove the case?

Answer from Cassidy Cash:

The issue is that in number 9 he has proved a SINGLE CASE, not all cases. If I tried to prove to you that the sun is “Always” to the west and walked outside in the afternoon – would you believe my evidence? You would tell me to try in the morning and you would show me I was wrong. Here Raoul demonstrated that the statement is true in a PARTICULAR case – but he did not PROVE it is so in ALL cases. It so happens it is true in all cases – but hopefully you can see from this that a simple example is NEVER proof.

In Number 10 Similar to number 9 above, even 1000 examples showing me something does not PROVE anything. In fact all I need to DISPROVE 1000 examples is ONE example showing it does not work.

This is an important issue in science and in logic in general. Think about it. Even when you hear something on the news! How often do we find a particular example being used to argue truth? If someone steals from you have you proved ALL people are evil? No – you showed one example. Much of what people argue in society is from examples – which can be evidence of some larger truth – but not always. So like the word “TRUTH” the word “PROOF” is very powerful and has a very specific meaning. They do NOT mean sometimes or most of the time – they mean at ALL times. Now read John 17:17 and consider the word TRUTH and PROOF.

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Geometry Ch2.2 #30

Question from Amy:

For Question 30 on page 49 in the text regarding dry ice and carbon dixodide. Why is dry ice is a and carbon dixoide b. I kept getting the reverse answer compared to the answer key. It has stumped both my parents. Thanks.

Answer from Cassidy Cash:

According to page 47, “a” represents the word being defined, and “b” represents the definition. In number 30 on page 49, dry ice is the word being defined, and frozen carbon dioxide is the definition. Since both statements are true, you are learning what they say on page 47, that “if both a statement and its converse are true, we can write “a if b” and “a only if b” or, more briefly, “a if and only if b” The “a if b” and “a only if b” are given to you as numbers 1) and 2) on page 49. Number 30 is where you write out the “a if and only if b”

Does that make sense? I hope this helps.

God Bless, Cassidy Cash