Re: [MATHEDCC] Calculus Review Chapter

Bret Taylor (bret@shell.iag.net)
Wed, 31 Mar 1999 08:25:14 -0500

At 02:46 AM 3/31/99 EST, CoolMath2@aol.com wrote:
>In a message dated 3/30/99 4:43:35 PM Pacific Standard Time, bret@iag.net
>writes:
>
><< "All I know about trig is 'Sine is the y reading; tells you how far you
are
> from the x-axis. Cosine is the x reading; tells you how far you are from
> the y-axis." If you ask me to find the sin (150 degrees) I quickly draw a
> unit circle (in my head) and note that sine is the "short distance" so it is
> 1/2 and it is in the positive direction from the x-axis, hence the sin 150
> degrees is +1/2. (That whole process takes about 2 to 3 seconds.) >>
>
>This is precisely what I mean by "memorizing" the unit circle. I have had
>students that haven't had to do this.
>

Thanks. I figured that was what you meant. Unfortunately, I have had
(several) students come to me from high school and their HS teacher had
them memorize (by rote, with no understanding) the exact value of sine,
cosine, and tangent for every special angle. I would ask them to give me
the sine of 2pi/3 and they would have no idea how it to do it other than
draw a circle and start filling in blanks untile they came to 2pi/3.
I would ask them "Does the sine of pi/3 equal sine of pi/4?" They would
spout their memorized values and say no. When I asked why not, they were
clueless.
>Karen
>Orange Coast College
>www.coolmath.com
>
>

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