Unit Circle

what dont you understand specificly? you can look up the broad explanation in any mathbook or website.

its a tad like asking: i dont understand math. can someone explain it to me?

The unit circle is used in many proofs because a triangle within it always has a hypotenuse of 1 (because that is its radius). I think you prove the derivatives of asin, atan, and asec with a unit circle in calculus.

Its just a simple tool to create proofs.

It's used to define sin and cos for one. Which is the first time you typically encounter it.

CodeTitan,

Your question is fundamental, and there are better places on the web to ask. For example, check out the homework related websites listed in the Forum FAQ. (I know your question may not be homework, but it is exactly the sort of thing that a first class in trigonometry would teach.)

Try here

On a unit circle sin and cos can be expressed as y and x. The unit circle is the graph x^2 + y^2 = 1. You get the sin/cos of an angle from the intersection of the terminal side of the angle with the unit circle. For instance, the coord at (0,1) (90 degrees). Cos 90 = 0; Sin 90 = 1;

Okay, I was in a rush to type something...I'll be more specific.

Should I memorize a table of common values, or should I understand how the unit circle works? We are doing trigonometric algebraic equations in math class, and I do not see which method for using the unit circle is better.

Really you need to do both. Learn the common table (pi/6, pi/4, pi/3 or 30,45,60 degrees respectively) and how they actually related to the unit circle. What happens if I want to know 4*pi/17 ? You don't need to memorize that, but if you have the common ones memorized and you understand how the unit circle works it is incredibly simple to figure it out.

Edit: or subsitute caek for pi, if you so prefer [grin]