SL Math

Unit Circle 

Hello everyone! 

     Welcome back from Mardi gras break! Recently in SL Math class we have been introduced to the unit circle! 

     We completed the first part of the book, which are chapters 1 to 7. We wish to complete the second part of the book before the end of the year. I think we're working on track according to Ms. Crystal's calendar and will complete the entire book by next year. There are only 4 sections in the book. So far we've learned a lot of material in little time. 

     Now we're working on the unit circle. Below you will find a picture of the unit circle. According to Wikipedia the unit circle is "a circle with a radius of one that is frequently the circle of radius one centered at the origin (0,0) in the Cartesian coordinate system in the Euclidean plane". The unit circle is something that must be memorized in IB because it will not be provided in the exam, however it will be used. The unit circle can be measured in both radians and degrees. Specific equations are needed for converting a number from radius into degrees. 

     According to Wikipedia the definition of radian is "the plane angle subtended by a circular arc as the length of the arc divided by the radius of the arc. One radian is the angle subtended at the center of a circle by an arc that is equal in length to the radius of the circle." According to mathopenref.com the definition of degrees is "a unit of angle measure. A full circle is divided into 360 degrees. For example, a right angle is 90 degrees. A degree has the symbol ° and so ninety degrees would written 90°. In other words, degrees and radians are both units to measure an angle. The equations to convert radian to degrees is to simply multiply the number of degree by 180°/(Π). The formula to convert from degrees to radian is to simply multiply the number of degrees by Π /180°.

Here is the unit circle: 

Thanks for reading!

-Melissa S.