Video Transcript
Express the following set using
interval notation. 𝑋 is equal to the set
containing lowercase 𝑥 where 𝑥 is greater than or equal to two and 𝑥 is a
real number.
First, we know that since 𝑥
could be greater than or equal to two but has no upper bound, we’re going to
represent this as an unlimited interval. It has no upper limit. So we can write the upper limit
as positive ∞. Remember, of course, that when
we do so, we cannot easily define or quantify positive ∞. And so, we use a round bracket
to represent an open interval at that point. We do, however, want to include
the number two. And so we represent our answer
as a left-closed right-open interval. Specifically, the set 𝑋 using
interval notation is represented by the left-closed right-open interval from two
to ∞.
