00:01
All right, for your question number one, you are given a graph and you are asked to estimate frequency and amplitude.
00:07
Now, i'm just going to draw the positive part of this graph because we can answer it just from that.
00:14
So the positive y -axis here goes up to 5 and down to negative 5.
00:25
And your x scale, which is your time, goes out to 10 seconds.
00:30
Now what we can see in this graph is it appears to start about right here.
00:36
It goes down, back up, down, back up, down, back up, and then seems to be hitting here.
00:55
Now, first step for frequency.
00:59
Frequency is the number of complete cycles per second, or the number of cycles per second.
01:07
So starting here, i can see that that represents one cycle.
01:14
Then we see a second and a third.
01:20
Now, so we have three complete cycles.
01:24
One here, one here, one here.
01:29
But i kind of want to use the 10 to help me, so i need to determine what fraction of a cycle this part is.
01:35
This part right here would represent one quarter of the total cycle.
01:44
So i'm going to say that we have 3 .25 cycles in 10 seconds.
01:55
Now to get that frequency, we need to divide.
01:59
So go ahead and take 3 .5 divided by 10, or 3 .25 divided by 10...