Help with Set questions please

[Flook]

Homework Statement

Hi, I need help with a couple of Set questions I just can't get my head around.

The question starts with:

Let

A = (-1, -2, 1, 2, 3, 5)

List the members of the following sets:

i) (x $\in$ R: x = m/n for m, n $\in$ A)

ii) (x $\in$ Z: x = m/n for m, n $\in$ A)

Homework Equations

The Attempt at a Solution

R will be real numbers and Z will be integers? I just can't seem to understand the rest. Any help ould be greatly appreciated.

Thanks

 

[SammyS]

Homework Statement

Hi, I need help with a couple of Set questions I just can't get my head around.

The question starts with:

Let

A = (-1, -2, 1, 2, 3, 5)

List the members of the following sets:

i) (x $\in$ R: x = m/n for m, n $\in$ A)

ii) (x $\in$ Z: x = m/n for m, n $\in$ A)

The Attempt at a Solution

R will be real numbers and Z will be integers? I just can't seem to understand the rest. Any help would be greatly appreciated.

Thanks

For i:

Generate all of the fractions you can make from the elements of set A, but using one element for the numerator and one element (possibly the same element) the denominator.

For ii:

Do the same as for part i, except you keep only the fractions which simplify to be integers.

 

[Flook]

Thanks for your response!

So for i)

I use A = (-1, -2, 1, 2, 3, 5) and make fractions, every possible combination?

-1/-2 = a half 1/2, but I wouldn't list that as it is not in set A?

so next would be -1/1 which is -1, so that is in set A?

I still don't get it I think.

 

[HallsofIvy]

No, the results don't have to be in A! You need to form all possible fractions- as the problem said, m/n with both m and n from A. All of those will be in (i) but only those that reduce to integers will be in (ii).

 

[Flook]

Ahh ok thank you HallsofIvy!