This problem demonstrates WeBWorK questions where the answer is a list of numbers or an interval.

Enter the first three numbers of the form $n^2$, where $n$ is a positive integer, as a comma separated list.

You could have entered your answer as "1, 4, 9" (without the quotes), or as "4, 1, 9", or as "2 ^ 2, 1 ^ 2, 3 ^ 2". The order of the numbers does not matter, and you can still let WeBWorK evaluate expressions for you.

---

Now we will enter a few intervals from the real line. WeBWorK can handle standard interval notation. In each case, we will describe the set in a couple of ways, and then show you how to enter it. Let's start with real numbers satisfying $2\le x <5$. The usual interval notation for this is $[2, 5)$.
Enter it just as shown:
Note, you can follow the usual WeBWorK conventions when entering the numbers in the interval, so you could also enter [ log(100), 2**2 + 1). Try it. Previewing your answer can help here too if you are having WeBWorK evaluate your answer.

With intervals, there is a difference between square brackets [] (which mean to include the end point) and parentheses () (which mean to not include the end point), and you will need to get them right to have the interval correct.

---

If we want to enter an interval where one side is unbounded, such as the real numbers greater than 3, we would normally write $(3, \infty)$. Since computer keyboards do not come with an infinity symbol, we just write out the word infinity . So, enter (3, infinity).

If we had wanted $-\infty$, we would type -infinity instead

---

Finally, sometimes intervals come in more than one piece. For example, the inequality $x^2 \ge 25$ is satisfied with $x \ge 5$ and also when $x \le -5$. This would be normally written as the union of two intervals: $$(-\infty, -5] \cup [5, \infty)$$ To type this into WeBWorK, we just use a capital U for the union symbol: (-infinity, -5] U [5, infinity)

When using unions of intervals, the order of the smaller intervals does not matter, so you could also enter [5, infinity) U (-infinity, -5].

---

Be aware that if you enter intervals which overlap, such as [2, 10) U (7, 15), WeBWorK will expect you to simplify it into a single interval, in this case [2, 15).