Mary's 3rd?! 4th?!? blog.

On our blogs, we are supposed to explain what we learned, but i'm having major trouble with everything this week. I took the time to re-do homework from the week to try and better understand what we're doing.



Let's start off in 8-1



This section is about solving for (theta) which we were told to use as 'x'. Then after you get the trig function and the theta by themselves, you take the trig function inverse of the number. Then you find the quadrants where the trig function is positive, and those two numbers will be your answer.

ex. 4cos(theta)=2
cos(theta)=1/2
cos(-1)(1/2)=(theta)
plug that in your calculator
60!
cos 60 is positive
so what other quadrant is cos positive
c'mon.. you know this...
its quadrant 4!
so how do we get to q4?
let's refer back to the notes.
i actually don't have an example b/c i didn't copy one from charlie, so i'm hoping this is correct.
to go into quadrant 4, you make negative, and add 360.
so we get -60+360=300degrees
so your answer is 60 and 300, i think.
please correct me if i'm wrong.

Moving on to 8-1 and 8-2 overlap.
honestly, all i know from that section is that if the problem says find "inclination" that you have to use m =tan(alpha)
and that if it says find directon angle that you use tan2(alpha)=b/a-c

Let's go on to 8-3!

here are the fomulas we were given to work this section
y=Asin(Bx+/-C) +/-D
y=Acos(Bx+/-C)+/-D

to graph these, here are the steps
1.follow the steps for graphing with a period change.
a)take all 5 points
B)divide by B
C)sketch
2.add or subtract c from those 5 points
3.move all y values up D or down D

now that i go over the notes, and i'm gonna work some more problems, this really isn't that hard.
the example is really long, but it follows these steps exactly.. do it on your own... haha.