Section 3.5 in the house!

Lession 3.5 by Paul Weitekamp

Ok guys, this section is about circular functions. It is basically the same kind of periodic functions we've dealt with before, but with radians instead of degrees.

So basically...
there are three key points to this section.

1. We have to distinguish between functions in degrees and functions with radians...

-Theta (the symbol won't show up) is used for functions with degrees.
-X is used for functions with radians.


2. The period for radians is found differently...

Whereas before in the equation: y=C+A sin B (x-D), B = 360/ period
With radians: B= 2Π/ period

3. Another important point we went over in class was that if you draw a line from the origin to the circumfrence of any unit circle, see figure below, then Cos x = u and Sin x = v.

This is true because the line from the origin to (u,v) is really just a radius to the circle and the radius = 1 in a unit circle. So....

Since Cos x = u/1 then, Cos x = u and Since Sin x = v/1 then, Sin x = v

Example Problem- What is the period of a sinusoid with the equation:

y= 6 + 3 sin ((Π/4) x- 7)

Ok then that's pretty much the lesson. Any questions don't be afraid to post them. And before i'm done i'd like to give a shout out to the homies in Virginia, keep it real.

LEO IS NEXT!?!?!??!?!

For more information see http://www.cis.edu.hk/sec/math/ib/higher/trig/CircFunc&Trig.htm