My 3rd post?

This is supposed to be on 8-1 through 8-3 but I don't really know much from 8-1 because I missed most of that section because I was on vacation. The rest of it I think I know fairly well though. Unfortunately I left my notebook in my locker at school so this blog might not be too good...

Anyway, I'm lost on section 8-1 so I guess I'm just going to talk about section 8-2.

8-2

This section was finding the Amplitude and Period of sine and cosine graphs.

First you need to know the formulas y=AsinBx and y=AcosBx

A stands for the Amplitude and B for the Period.

Amplitude represents the highest point on the graph and Period is how often the graph repeats itself.

You have to find the absolute value of A and divide B by 2pi.

The result of that will give you your Amplitude and Period.

Next you need to find the first five points of the graph and to do that you need to find the quotient of B from these points:
1.) o
2.)pi/2
3.)pi
4.)3pi/2
5.)2pi
And then just sketch your graph and you are done.

Sine graphs start from or pass through the origin and cosine functions start from a particular point.

Example: y=2sin4pix

Amp=2 Per=1/2 ( 2pi/4pi pi's cancel and 2/4 simplifies to 1/2 )

1.) 0/4pi = 0
2.) pi/2 / 4pi = 1/8
3.) pi/ 4pi = 1/4
4.) 3pi/2 / 4pi = 3/8pi
5.) 2pi/ 4pi = 1/2

* Your fifth point and you period should match, that is a way to check if you found everything correctly

After that all you have left to do is graph, the sign of the Amplitude (+ or -) determines which way the graph opens up.

Then you're all done, yippee!