Feroz's Epic Blog #2

It's two in the morining and I have nothing to do, so let's do a blog!

I shall be covering section 8-1 because those are the only notes I can find. I can guarantee you this will come back to bite me in the ass. Anyway, let's get started.

Unlike the previous sections, I actually get this one.

What we're doing here is solving for theta and in order to do that, we gotta get the trig function by itself and get the two answers for the inverse. Simple enough?

First, you must determine whether the angle is positive or negative based on the trig function.

This section requires you to move from the first quadrant to the other three for some reason. I dunno, but here are the steps:

To QII: Make the number negative and add 180
To QIII: Just add 180
To QIV: Make the number negative and add 360

Now that you know what to do, let's try an example:

4 sinΘ = 2

Now divide both sides by 4, which leaves you with:

sinΘ = 1/2

Tip: It's easier if you just consider this first part as an equation. Think of sinΘ (or whatever trig function you're solving for) to be a variable, like x. If you're solving for x, you want to get it by itself. Like this: 4x = 2, so x = 1/2)

Now, looking back to your trig chart, you can see that π/6 = 1/2.

Now, what is π/6 in degrees? Well, you should know that π = 180, thus making our fraction 180/6. Reduce that, and you're left with 30. That means sin π/6 = 30.

This is the part where you'll need to get two answers. You should know this already but sin is related to the y-axis, and since we determined that 30 is positive, we need to know in which quadrants is sin positive in, which are QI and QII.

We now need to find an answer for both quadrants, hence the two answers part.

We already have QI, which is 30. Now all we need is QII, so look back at those steps I gave you in the beginning to get to the different quadrants, we gonna be using those. To get to QII, we have to make 30 negative, and then add 180. So QII = 150.

Final answers: Θ = 30 degrees and 150 degrees.

So that wasn't too bad. You need to know your trig chart to be able to do these though, which is a real pain in the ass. The only ones I really know are sin and cos, so I should probably work on that.