The Unit Circle: using to find cos 7pi/6 (need lessons)

[meow]

Hi

I would like to know how to use the unit circle in proper way. I have studied at highschool but I passed without understanding everything fully. Now I need my math skills for higher studies.

1. I would like to have the unit circle explained fully (If any of you can do that, or redirect me to some website that can help me),I want to know a good way of memorizing the degrees and radians and to learn how to draw triangles in the unit circles to help me determine for instance which angles that have certain sinus or cosinus values.

2. I need help in determineing cos 7pi/6 with help of the unit circle.

 

[stapel]

I would like to have the unit circle explained fully

As you no doubt recall, the unit circle comprised a large chunk of your textbook, possibly even an entire chapter. Obviously, we cannot reproduce that here, let alone explain the material at greater length and depth. Fortunately, there are just loads of lessons available online! :wink:

. . . . .Google results for "unit circle"

You may find it helpful to study the pictures, along with studying some lessons. The use of the unit circle often boils down to nothing more than remembering the "cycle" of the trig functions, remembering the signs of the trig functions in the various quadrants, and then reading the correct value from the picture (and then tacking on the right sign).

For instance, you would note how cos((7pi)/6) relates to cos(pi/6), how (7/6)pi relates to 0 and pi, and what the sign of the cosine is in the second quadrant. Then you'd read your value from the circle (or just go with the reference-angle value that you've memorized).

Have fun!

Eliz.