Question

For the sets A = (1, 2], B = [−2, 1] and U=Reals, there's some identities I have to find for them I'm not familiar with. A^c , B^c , A ∩ B, A ∪ B, A\B, B \A, and A delta B

Answer 1

\[A^c=\{x|x\notin A\}\]so in this case it would be
\[(-\infty, 1]\cup (2,\infty)\]

Answer 2

is there a list of these identity functions somewhere? I think I could figure it out if I had something to refer to, but I don't unfortunately

Answer 3

hold on

Answer 4

like, I'm not sure what A^c or A delta B or A \ B even mean

Answer 5

A^c means everything not in A

Answer 6

A\B means everything that is in A but not in B

Answer 7

and i am not sure about the delta notation, but my guess it it means everything in A or B but not both

Answer 8

Well, I guessed it meant delta because the symbol used is a small triangle.

Answer 9

aks
\[A\Delta B= (A\cup B)-(A\cap B)\]

Answer 10

not standard notation, usually you see
\[A\oplus B\]

Answer 11

you ok with unions and intersections?

Answer 12

so the big U is the union of set A and B, meaning all their values together? and the big n is the intersection, only what they have in common?

Answer 13

yes

Answer 14

http://www.youtube.com/watch?v=En8fI2ixepo

Answer 15

thanks a lot man!

Answer 16

yw