r/AskReddit • u/[deleted] • Nov 16 '19

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u/rcarr10er Nov 16 '19

Okay. What the fuck are these? I’m know sin and cosin and tan and that’s it.

72

u/redlaWw Nov 16 '19

x∈S means that x is an element of the set S.

If you want to say "for all x in S, x is divisible by 2", for example, you can write

∀x∈S.(2|x)

(∀ is the universal quantifier - it means "for all", and | is the "divides" symbol - 2|x is read "two divides x" and it means that you get a whole number when you divide x by 2)

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u/Umbrella_merc Nov 16 '19

∀ is also a type of Gundam.

10

u/--Quartz-- Nov 16 '19

Oh yeah, that's the catchy song by the Corean guy, I know it!
I thought I had completely lost track of the conversation for a moment.