Discrete Math 2-Tutorial 13 - Example 1: Inclusion/Exlusion

Example 1 of inclusion and exclusion principle.

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[polyhydragames]

What software are you using? Thanks for the videos btw helped me a lot (in general)

[coursehack]

@SongBirdJesusFreak its part of the course; im not doing them because they're difficult or simple... im following a certain list of sections im planning to cover.

[Gergeosson]

Never mind :) I figured it out. Great tutorial, thanks!

[amadddd]

Thanks alot. this really helped me on my test

[coursehack]

Thats the point of Inclusion Exclusion principle... you have a sample set S0, but it has too many, so, you have to subtract S1, but now you've subtracted too much
So, to make up for that, you add S2, and so on...
you keep on adding and subtracting to get the right result (not too much, not too little).
Hope that made sense :)

[coursehack]

yeh, pretty much... most questions can be solved like that... take the negation of the condition... then follow the procedure and use the formula....

[amadddd]

Can most inclusion/exclusion problems be broken down this way?
Are there any other applications of inclusion/exclusion that you may not have shown?
And thank you so much for these videos

[Gergeosson]

Isn't s3 a subset of s2, which is a subset of s1, which is a subset of s0?
I'm thinking that s1 is the set of cases in which there are at least 1 occurrence of 3 consecutive letters, and that this includes cases with 2 or 3 occurrences as well.

In that case, isn't the set of cases with no occurrences of 3 consecutive letters just s0 - s1?

If that is not the case, can you explain why, and maybe draw a venn diagram?

[rafaeltsuzuki]

Shouldnt be S0 - S1 (-) S2 - S3, instead of + S2?