Question

When expressing sets, you may write "inf" for infinity and "U" for union.

Write the complement of the given set in interval notation: (6,[infinity])

Answer 1

`(-\infty, 6]`

Explanation:

The complement of a set Α, is everything that is NOT in A. In our case we want to compute the complement of the interval
`(6,\infty)`, which denotes the set of all numbers greater than 6. So, which numbers are NOT in that set? Those that aren't greater than 6, which is the same as saying those that are less than or equal to 6. That set is written in interval notation as
`(-\infty, 6]` (where the square bracket means that 6 is being included in that set)