July 2010 Archives

One of my Summer Precalc students asked:

So I am really taking this course so that I can hopefully do well in calculus next semester. You said that the unit circle is really important but I am having a hard time memorizing it. I am having a hard time with the sine and cosine and figuring out the angle in radians in any quadrant other than the first one. Do you have any segestions (sic) on how I could memorize them easier?

Here is how I replied and if you, as a future Oxbow AP calculus student are also having a difficult time with that part of the summer review, I suggest you do this also:

Part (a) Memorize the sine and cosine of 30^o (π/6), 60^o (π/3) and 45^o (π/4) (see what purplemath.copm recommends on this (the bottom of the page http://www.purplemath.com/modules/specang.htm)

Part B (b) Know how to draw the reference triangle and find the reference angle

Then apply part a to part b remembering ASTC for the + and -

If you need tangent, secant, cosecant or cotangent, just remember the basic identities.

This is how I do these kind of problems.