## anonymous 4 years ago 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

1. anonymous

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

2. anonymous

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

3. anonymous

hold on

4. anonymous

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

5. anonymous

A^c means everything not in A

6. anonymous

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

7. anonymous

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

8. anonymous

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

9. anonymous

aks $A\Delta B= (A\cup B)-(A\cap B)$

10. anonymous

not standard notation, usually you see $A\oplus B$

11. anonymous

you ok with unions and intersections?

12. anonymous

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?

13. anonymous

yes

14. anonymous
15. anonymous

thanks a lot man!

16. anonymous

yw