Discrete Math: How do you study for it?

[greedostick]

Just started discrete math.. It's online which I'm not happy about. The book is horrible, and doesn't explain things well. This is my first discrete class, it seems easy but I just don't know what to study, or really how to study is most effectively. This is the first week, we're taking sentences and rearranging them for stuff like contrapositive, and doing things like making truth tables. The book doesn't explain these tables at all, it just says work in reverse...

I know these first few weeks are crucial, does anyone have any tips to get off on on the right foot??

 

[evil wasabi]

You need to be more discreet about the fact you are taking this class

What math classes have you taken so far?

 

[StevenK]

Overtly

 

[greedostick]

You need to be more discreet about the fact you are taking this class

What math classes have you taken so far?

I've taken one statistics class, and from algebra all the way through calc 1. All the math I have left is this class, Probability Stats, and Calc 2. All I have besides these damn math classes are core computer science classes. So I have to knock this flipping math out so I can focus on these classes, and not be miserable anymore, because the computer science classes are fun.

I have managed to get A's and B's thus far in all my math, so I know I can do this. This class is just weird though. It's like reading sentences spoken by some old man with dementia and turning them into computer robot sentences.

 

[ookitarepanda]

Greedo, if you ever wanna skype or facetime or something, I'm sure we could work some'n out. I'm a math teacher and stuff...

 

[ebinsugewa]

I've taken two semesters of discrete and also tutored for it. Don't apply your expectations from previous math courses - discrete can be much less 'formulaic' and more 'logical'. At times you'll very rarely even deal with numbers at all.

Truth tables and statements are very easy, don't worry you'll pick them up quickly.

Brief rundown on statements:

Take a statement of the form 'if P then Q' ie "If a person is male, then they are tall."

The converse is 'if Q then P'. Keep both truth values but swap their positions. "If a person is tall, then they are male."
The inverse is 'if not P then not Q'. You invert the truth values of both original parts but do not change their order. "If a person is not a male, then they are not tall."
The contrapositive is 'if not Q then not P'. You negate the converse. "If a person is not tall, then they are not a male."
Note: the contrapositive is the only one to always have the same truth value as the original statement.

Teachers can be sticklers for certain phrasing or wording with these kinds of problems, try to learn in class what things they harp on.

Taking a discrete class online is going to be rather difficult - like you mentioned the books can be wordy and obtuse, and not being able to talk through these concepts in person is going to make them a lot harder to understand. Discrete is incredibly simple compared to other branches of math but can require the most thought and discussion to unravel the meaning contained within. Try posting some examples of truth table stuff you're having difficulty with.

 

[greedostick]

Thanks for the help you two. This class does seem easy thus far, it's just a matter of getting off on the right foot early. So I am Busting my ass this week. Doing online is really going to hurt me this class. Normally I live in the math lab but as of recently I am without vehicle. Here is a part I am having problems on..

I am confused about how to check back to the chart after breaking down a sentence, and getting it back in order in the solution. Here is what I am talking about...

CONDITIONAL CHART:

CONDITIONAL P ---->Q / CONDITIONAL Q----->P
Q IS NECESSARY FOR P / P IS NECESSARY FOR Q

THE QUESTION:

P: WE ARE HUMANS
Q: WE LOVE OUR NEIGHBORS
R: WE LIVE IN PEACE

Loving our neighbors is necessary for living in peace.
so Q IS NECESSARY for R
so the answer is R ---->Q

So when I break down the "loving our neighbors" question and get Q IS NECESSARY for R when I take my first step in breaking it down all is good. I understand this. But I am confused how I am suppose to refer to the conditional chart, and if there are any tips or tricks for doing this. I would miss this every time and put Q--->R instead of R--->Q.

I don't know if I can explain clearly what I am thinking here, but is seems like since in the first step I get Q IS NECESSARY for R, that Q comes before R, so maybe I should look at the part on the conditional chart P--->Q since P comes before Q. But then when I look at the top side of the chart I selected I get really confused how to apply the switched letters to my answer. It's like I have too many sets of 2 letters in my head. I have to be making this harder than it needs to be.