Question

Exercise 1.Can someone please help me with this? I tried it sometime last week and was asked “what do the parenthesis mean?” and nothing else. So I’m not sure what to do.

Answer 1

In order to solve this exercise, you need to remember the following:

- There are different types of intervals.

- Open Intervals have this form:

`(a,b)`

In which the endpoints "a" and "b" are not included.

- Closed Intervals have this form:

`\lbrack a,b\rbrack`

Where the endpoints "a" and "b" are included.

- Half Open Intervals can have this form:

`\begin{gathered} \lbrack a,b) \\ \\ (a,b\rbrack \end{gathered}`

These include one of its endpoints.

In this case, given:

`(-1,\infty)`

You can identify that it is an Open Interval. Then, you can set up that:

`x>-1`

Knowing this, you can determine that the values in the interval are greater than -1, but -1 is not included.

Hence, the answers are:

`\begin{gathered} x=0 \\ \\ x=3 \end{gathered}`