# Homework Help: Do I have memorize the entire Unit circle ?

1. Jun 5, 2010

### majormuss

Do I have memorize the entire Unit circle ??

1. The problem statement, all variables and given/known data

I am currently takin a trig class and I was a bit daunted by the Unit Circle and all its special angles. My question is... Do I haveto memorize the entire Unit Circle and its angles?? Will it be given to me during exams(as cheat sheet)??

2. Relevant equations

3. The attempt at a solution

2. Jun 5, 2010

### Tedjn

Re: Do I have memorize the entire Unit circle ??

You'd have to ask your teacher that. Common angles you might be expected to know without a cheat sheet are 0, pi/6 (30 deg), pi/4 (45 deg), pi/3 (60 deg), pi/2 (90 deg). That's not too much, and you would only need to know them for sine and cosine. Probably, you can use triangles to remember them more easily. Just knowing these means you know the analogous angles in the other quadrants too.

3. Jun 5, 2010

### GreatEscapist

Re: Do I have memorize the entire Unit circle ??

It's good to.

We had to, but I took a college class. It's not as hard as it looks- memorize thetas first- they're easy once you see the pattern- then when you see the pattern it will be really easy to memorize. =)

4. Jun 5, 2010

### Redbelly98

Staff Emeritus
Re: Do I have memorize the entire Unit circle ??

I agree with Tedjn, and if you consider that 0° and 90° are pretty trivial (sine and cosine are either 0 or 1, as is easily seen by looking at a unit circle), then there are only 3 angles (30°, 45°, 60°) whose sine and cosine need to be memorized. This involves remembering 3 numbers:

$$\frac{\sqrt{1}}{2}, \ \frac{\sqrt{2}}{2}, \ \frac{\sqrt{3}}{2}$$​

Obviously the square-root sign is not necessary for the first one, but I included it as it may make this sequence of numbers easier to memorize.

5. Jun 5, 2010

### shelovesmath

Re: Do I have memorize the entire Unit circle ??

Yeah, it's a good idea. It will make your math life easier.

6. Jun 5, 2010

### majormuss

Re: Do I have memorize the entire Unit circle ??

thanks.... i'll try to incorporate your suggestions!!!

7. Jun 5, 2010

### shelovesmath

Re: Do I have memorize the entire Unit circle ??

One thing that helped me to understand it better was when I realized it's basically just one quadrant folded over onto itself twice.

8. Jun 5, 2010

### GreatEscapist

Re: Do I have memorize the entire Unit circle ??

That's really true. Just learn one of them, and you'll be on your way.