#Discrete Math problem

23 messages · Page 1 of 1 (latest)

dark micaBOT
sudden nacelle
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it's just rearranging |A u B|=|A|+|B|-|A n B|

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@shrewd sorrel

shrewd sorrel
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what do u mean

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ohhh

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i didnt know that was a thing u can do

sudden nacelle
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yeah the cardinalities are just numbers

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atleast for finite sets

shrewd sorrel
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so whenever it asks to find the intersect of two sets like that u would do |A|+|B|- |A u B|=|A n B|

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and for A1UA2 why is it not just A1+A2 why do we do the difference method

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sudden nacelle
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overlap

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:)

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or well

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yeah its overlap

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and also

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you're basically just taking out all the solutions that dont work

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^ it's actually mostly this

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note that the thing your subtracting got flipped

shrewd sorrel
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oh gotcha

sudden nacelle
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i.e. since you want all solutions with x<=3 or y<=4, you take all, do demoivre to get x>=4 AND y>5, and subtract thato ut

shrewd sorrel
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And how is this problem different from that

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Is it cus in here we are looking for the number of ways to split up?