Question concerning sets using unions.?

Question

Calculate...U with infinity on the top and n=0 underneath the union. {-n, n}

I was thinking all real numbers or is it looking for specific numbers.

Thank you.

Answer 1

The notation for values of n will only include non-negative integers. That is, n will take on the values 0, 1, 2, 3, 4, 5, ..., positive infinity. So the sets being united are {0, 0}, {-1, 1}, {-2, 2}, ..., {-inf, +inf}. As a result, every integer is included here, positive and negative. But no non-integers. The union of these sets is therefore Z, the set of all integers, rather than R, the set of all real numbers.

Answer 2

it is just the complete set of integer from negative infinity to infinity

Answer 3

the set will start to look like this:

{0,0} U {-1,1} U {-2,2} U {-3,3} U ...

the overall set would be:

{{0,0} , {-1,1} , {-2,2} , {-3,3} , ... }