Question

i need help with i and j

Answer 1

this is what i did for I

Answer 2

You mis-interpreted B - C which means the elements of B that are not in C

Answer 3

Actually, I take that back. What you've done is almost correct. \(B - C = (3, \infty)\)

Answer 4

oml.. then how would i start it lol

Answer 5

oh wait how come its not bracket for 3?

Answer 6

Because 3 is included in C. We want the elements of B that are NOT in C.

Answer 7

So the next step would be to name the interval \((3, \infty)\) just to make it easier to do the next step.

Answer 8

So let \(D = (3, \infty)\). Now find \(A - D\)

Answer 9

After you find that interval, you'll be done with problem I

Answer 10

BTW, the final result you have is almost correct as well.

Answer 11

so then it would be ( 3 , infinity)?

Answer 12

What did you get for your final final result? Do you remember?

Answer 13

And actually I'm going to say [-5,-3] is correct because B - C does not include 3 but A does. So don't even change your final result.

Answer 14

So funny thing, your intermediary step had a small error, but your final result is still correct.

Answer 15

Looks like you don't need much help with this after all.

Answer 16

i sometimes get confused when to write parenthesis and brackets

Answer 17

Parentheses just means the endpoints of an interval are not included. Brackets mean include the endpoints. Something like that.

Answer 18

so for i got this

Answer 19

What do you mean? We already went over i

Answer 20

@xXMarcelieXx I don't understand what you just wrote. Did you mean, "so far I got this"?

Answer 21

sorry i was working on it lol

Answer 22

for j *

Answer 23

Okay double check your A - B. Remember, A - B means the elements of A excluding the elements of B.

Answer 24

hmm i still dont get it lol

Answer 25

If you can't do j, then explain how you did i

Answer 26

i just did i by doing the number lines though
and making sense of it lol

Answer 27

isnt A-B umm ( -5 , 1) ?

Answer 28

Actually, it's [-5,1] which you wrote correctly but when you made your number line, you did it wrong.

Answer 29

when you said " A - B means the elements of A excluding the elements of B "
do you mean that we only include the numbers from A that arent in B ?

Answer 30

correct

Answer 31

But do you see where you wrote A - B = [-5,1] which is different from the number line you created for A - B?

Answer 32

oh truee

Answer 33

so then the final answer will change?

Answer 34

It will indeed

Answer 35

hmm would we have union?

Answer 36

oh wait nvm lol
so then we would have ( 1 ,3)

Answer 37

You should draw number lines for this one.

Answer 38

You work a lot better by drawing the number lines and posting them here

Answer 39

Okay, so how come you did not graph the number line for (A - B) - C?

Answer 40

oh i graphed it into parts first

Answer 41

but we would get this as a final answer
( A - B ) - C = (1 , 3)

Answer 42

Okay so you have the set for A - B. And then when you excluded all the elements that include C what are you left with?

Answer 43

Aren't there more elements in C than there are in A - B?

Answer 44

yeah there are more elements in C

Answer 45

we would have more numbers in the - infinity and positive numbers right

Answer 46

Do the elements in C INCLUDE the elements in A - B?

Answer 47

@xXMarcelieXx did you die?

Answer 48

oh wait no

Answer 49

im still here lol

Answer 50

Okay

Answer 51

okay so then

Answer 52

So then answer my previous questions

Answer 53

umm they dont right

Answer 54

Go back and look at the number line for C again and ask if the number line for A - B is included.

Answer 55

oh yes it is included

Answer 56

Okay, but aren't you supposed to be excluding everything in C from A - B?

Answer 57

yeah

Answer 58

So basically you already performed A - B. Now you must perform the MINUS C part. In other words, you must remove every element containing C. When you do that, what's left?

Answer 59

@xXMarcelieXx are you still alive?

Answer 60

yes im trying to figure it out but i think its umm 3 , infinity ?

Answer 61

Do you remember the number line for A - B?

Answer 62

State both intervals here for A- B and C

Answer 63

A - B = [ 5 , 1 ]
C = (- infinity , 3]

Answer 64

Right and [-5,1] is included in C correct?

Answer 65

yes

Answer 66

But MINUS C means to remove all of C correct?

Answer 67

oh wait i think i made a mistake with this problem for A
aaahh

Answer 68

How?

Answer 69

i put A was [ -5, infinity) which was suppose to be [ 5, 4) lol
i misread it

Answer 70

Okay.

Answer 71

one sec let me redo it again. sorrry lol

Answer 72

Surprised I didn't catch that myself

Answer 73

im half asleep thats why lol

Answer 74

smh

Answer 75

What course are you taking?

Answer 76

intro too math proofs

Answer 77

I see. Why are you taking intro to math proofs? What is your major?

Answer 78

math teaching and getting a minor in finance

Answer 79

they say its useful for math teaching lool

Answer 80

Good luck in your endeavors

Answer 81

thanks lol i will be back later to finish this stuff