Taylor's 5th (or 6th I have no clue XD) Blog

These are my notes from lesson 8.1.

In this lesson we will be solving for THETA. In order for you to be able to solve for Theta you need to get the trig. function by itself and then you need to take an inverse of it. An inverse will have two answers, but there may be exceptions to this rule if the question asks you to just find one quadrant. Any way, you need to find where an angle is based on the trig function and then you need to tell if it is negative or positive.

These are the steps:

First, you need to take the inverse of the number so that you can find the First Quadrant angle.

Then you simply need to remember this in order to find the other answers:

Quadrant 2, you need to make the first quadrant angle a negative and add 180 degrees to it.

Quadrant 3, you just need to add 180 degrees to the first quadrant angle.

Quadrant 4, you need to make the first quadrant angle a negative and add 360 degrees to it.

Now let's solve some problems!!

(REMEMBER I DO NOT KNOW HOW TO PUT A GRAPH ON HERE SO PLEASE NOTE THIS. WHEN I SAY DRAW A QUARDNENT PLANE DO SO AND CHECK THE ONES THAT I TELL YOU TO OK!!)

Solve for Sin A= 3/8 for A.

Sin A = 3/8 First, write the equation down.

A= Sin^-1(3/8) Then put the equation in inverse form like I just did.

A= 22.024 degrees Then you find the inverse. Ok, now draw you quadrant plane. Now since our Sin is positive we need to put a check in the quadrants where Sin or Y would be positive. Which is the First and Second Quadrant. So since we have the First Quadrant already we just need to find the Second Quadrant.

-22.024 degrees + 180 degrees= 157.976 degrees Finally you just use the formula that I gave you to find the angle of the Second Quadrant and this is your answer.

So your answers should be 157.976 degrees and 22.024 degrees.

Let's try cosine next.

Solve for Cos H = 4/6 for H.

Cos H = 4/6 First, write the equation down.

H= Cos6-1(4/6) Then put the equation in inverse form like I just did.

H= 48.190 degrees Then you find the inverse. Ok, now draw you quadrant plane. Now since our Cos is positive we need to put a check in the quadrants where Cos or X would be positive. Which is the First and Fourth Quadrant. So since we have the First Quadrant already we just need to find the Fourth Quadrant.

-48.190 degrees + 360 degrees= 311.81 degrees Finally you just use the formula that I gave you to find the angle of the Fourth Quadrant and this is your answer.

So your answers should be 48.190 degrees and 311.81 degrees .

That is what I learned and my notes on Lesson 8.1.