[Discrete Mathematics] Midterm 1 Solutions

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Hello, welcome to TheTrevTutor. I'm here to help you learn your college courses in an easy, efficient manner. If you like what you see, feel free to subscribe and follow me for updates. If you have any questions, leave them below. I try to answer as many questions as possible. If something isn't quite clear or needs more explanation, I can easily make additional videos to satisfy your need for knowledge and understanding.

[KydroxHD]

You dont understand how much of a Godsend you are.
THANKYOUTHANKYOUTHANKYOU

[UnderstandingCode]

youre a great guy for making these, thanks dude

[Alionn]

I am 3 years old and I can understand this very good

[samiazaman]

Thank you so much for this Discrete Math series. When I will earn my own money, I will be so happy to support your channel through donations :')

[chesstanay]

For 7D, because <n, n, n> is not decreasing, but is counted in stars and bars, should it not be (7+3-1)C(7-1) - 7?
Note that (7+3-1)C(7-1) = (7+3-1)C(3)

[eimaldorani]

@27:00
The answer would be the same for increasing/decreasing/or any order sequence?

[Dezomm]

These videos have been phenomenal so far. Thank you.

[eimaldorani]

@27:50 Don't you think it is (9 choose 7)!?
or (9 choose 2)

Suppose we have the set A = {1, 2, 3, 4, 5, 6, 7}. How many ways can
choose 3 numbers to form a decreasing sequence? (Hint: < 6, 4, 4 > is decreasing.)

[mehmetozcan]

Thanks for your effort.
At question 6, either Derek works or Avery doesn't work what I understand is Derek and Avery are in a opposite working situation, so at the end of the question it says Derek doesn't work, so Avery works. According to this information Celina' s working situation is up to Brandon's situation. What I found that if Brandon doesn't work Celina works or its vice versa

[eimaldorani]

Is it necessary that the first digit be 1!? @25:25
@Suppose we have a binary string of length 15. How many possible strings
will have exactly 6 zeros?

[treehuggerlife]

Want to thank you for your videos. You have been helping me through this semester of Discrete Math. Grazie!!

[annulrsolformrkelse]

Am I the only one who understood task 9. (c) in a different way (37:28)?
Since the task mentions that order does not matter, I assumed that while it does not matter in which order you arrange the books on each shelf, it still matters how you distribute the 13 books onto the 3 shelves.
But after having seen your solution it seems to me that the task should actually state "How many ways can I arrange my textbooks if *all books are identical*?" instead.
Thanks for any reply and thank you Trev for your great videos!

[Amir-zrcb]

My english is weak but you explain really clear and simple and I understand well thank you❤

[skatomort]

At DM1 course, video 13, 4:15 you told us that statements can not contain variables. But here at 10:20, you state that c) is a statement. That is contradiction ...
As always I'm really grateful for your free content. Thank you teacher !

[mryoloTHEgreek]

So at 20:05 1, 3 is modus tollens and not disjunctive syllogism, sir you have it wrong because D or notA can be written as: A->D so A->D and not D from modus tollents is not A

[swagatochatterjee]

At @16:04 shouldn't the second column be 1101?

[LxE]

I might be wrong here, but from the notes I've taken from your videos, at 21:00 step 5 I have that Disjunction Introduction is the same as Addition (v i) wich says: P therefore P v Q. Is it correct to call it Addition? Is it ( v i ) or ( v E )?

[eimaldorani]

@07:40 Can we proof A − B = A ∩ B' without using Venn Diagrams, PLEASE!?

[jasonr]

Thanks for taking the time to make this! This is a great review.

[chubowu]

"mmm look at those melons, look at those melons she has" - TrevTutor