00:01
Write the domain using interval notation.
00:03
We have six graphs here, so we're going to write the domain for each one.
00:08
Let's take a look at graph a.
00:11
Graph a has a line where y equals 3.
00:16
We have no other restrictions on the x values, so our x's can go from negative infinity to positive infinity.
00:27
Now, with interval notation, when you have a square bracket, this means to include it.
00:36
When you have a round bracket, this means don't include it or not include it.
00:47
And then if you have infinity involved, you always have a round bracket because infinity never ends.
00:57
So we can't include infinity because it has no end.
01:01
So we're just going to put our rounded brackets.
01:05
Let's look at b.
01:06
B is again a straight line.
01:08
So it goes from negative infinity to positive infinity.
01:14
Graph c.
01:16
Here we have a quadratic function and we have our x values with no restrictions.
01:24
We do have a restriction on the range though.
01:26
But we're only looking at domain and remember domain is just your x values.
01:34
So again we have negative infinity to positive infinity.
01:40
So let's scroll to give ourselves a little bit more room.
01:44
Let's take a look at c.
01:46
Here we have a graph that stops where x is equal to negative 2.
01:52
We're not we can't go to negative 3 and we can't go to negative 2 but we will include negative 2, so we write negative 2 comma positive infinity.
02:04
Now let's say you don't want to include negative 2.
02:07
So now let's say x cannot equal negative 2...