00:03
Here we are going to use the intermediate value theorem to find an interval where this function is going to cross the x -axis.
00:14
We're going to approximate those zeros with a graphing calculator.
00:18
We use the table function to help get that approximation.
00:20
And then we're going to use the zero function to get an even better approximation.
00:25
There are several graphing calculators out there, so i'll kind of explain the basic process a little bit.
00:30
So you can apply it to whatever you're using.
00:32
And the first thing i did for this function is i did graph it, and i noticed it looked a little something like this.
00:39
So there were two intervals we were really focused on.
00:42
We did want to focus on that interval.
00:45
I'll use interval notation to write this between negative 2 and negative 1.
00:48
And we also want to focus on this other interval between 0 and 1.
00:53
So what i did is using that table function, i actually had my table start at negative 2, and then i had it count by just one -tenth so i could find a really tiny interval to help with the approximation.
01:06
So on that x -y table, when i did count by one -tenth, i noticed that as it went from negative 1 -6 -tenth to negative 1 -5 -tenths for the input, the function value went from above the x -axis to below the x -axis.
01:24
So with the intermediate value theorem, we know that somewhere in there, since we're going to, it's continuous, it must have crossed zero.
01:32
Since that, you know, approximately, you know, 2 ,800s that you see right there, since that's a little bit closer to the zero than the negative 1 in 3 tenths you see down below, we're going to approximate that the 0 is a little closer to the negative 1 in 6 tenths.
01:47
So why don't we say for an initial estimation, let's say like negative 1 and 5 ,800s, we'll go closer to negative 1 in 6 tenths than closer to negative 1 in 5 now on the other interval, i did the same thing.
02:00
I started my table at zero...