00:01
So we want to graph this equation and get some information.
00:03
So i'm not necessarily going to go in order.
00:05
I'm going to start with our angle here, which means 7x minus 4 pi for cosine has to go between 0 and 2 pi.
00:15
So i'm going to solve for x.
00:17
So i'm going to have 4 pi.
00:22
So this can be 4 pi is going to be between 7x and 6 pi.
00:27
So now i'm going to divide by 7.
00:29
So i'm going to have x is going to be between 4 7th and 6 pi.
00:34
So that tells you my starting point is going to be 4 pi over 7 and my stopping point is going to be 6 pi over 7.
00:42
So that tells me i'm going to have a period of 2 pi over 7.
00:48
Now i'm going to get the key points here by getting what's in the middle.
00:51
So that's going to be 5 pi over 7 when i get the average.
00:54
Now when i get the average of these two, i'm going to have to add and divide by 2.
00:59
So when i add that, i'll get 9 pi over 7 divided by 2.
01:03
I'll get 9 pi over 14.
01:06
I add this, i get 11 pi over 7 divided by 2.
01:09
I get 11 pi over 14...