First lesson of unit 1 Circular Functions

Hey guys this is Ruby and i'm going to summarize what we had learned in class today February 7th 2012.
                                         Degree and radian measure 1
. We went over labelling and angle with two rays by determining the vertex, initial side and terminal side
. If the rotation of the ray is counterclockwisethe angle is positive, if the ray is going clockwise, it is a negative angle.

                                  

coterminal angles

We learned that angles that share a terminal side are called coterminal angles.

Also, we went over how to find the quadrant in which  Ѳ is in and the negative/positive coterminal angles of that.

EX.) If you are given  Ѳ =120 degrees

To find quadrant

it will be in quadrant 2 because quadrant 1 ends at 90 degrees, and you add 30 to get 120 degrees which falls in the second quadrant

Positive coterminal angles

all you need to do to come up with some positive coterminal angles is add 360 degrees to your  Ѳ which in this case is 120.  120+360=480

480+360=840

*remember, if you add 360 and your # is a negative number, keep adding 360 until it becomes positive.

Negative coterminal angles

Finding negative coterminals is just as simple. All you need to do is subtract 360 from your  Ѳ

120-360= -240

-240- 360= -600

Radian Measure

we learned that π=180 degrees and 2π=360 degrees

To convert degrees to radian

Divide by 180

ex. convert 30 degrees into radians

30.π/180

divide 30 by 180 = π/6

To convert radians to degrees

divide by π

ex. convert 5π/4 into degrees

since π=180 , multiply 5 by 180 =900 and divide by 4

900/4= 225 degrees

That briefly sums up our lesson for February 7th 2012, hope you learned lots!