## Friday, February 22, 2008

### BOB Version 1: Circular Functions

Nope, not done blogging for today. Just doing my BOB…

And so, Circular Functions, the unit, put a lot of emphasis on the unit circle. Memorizing (no, not memorize, but remember!) the values using mnemonics was the muddiest thing that I didn’t like about this unit. But remembering the unit circle did help me out as we progress through the course. Also just as equally as muddy was the group work assignment, The Unit Circle Triangle. I didn’t like that assignment ‘cause of its “challengingness.”

I remember in gr.11 we were studying how to graph trigonometric functions and Mr.K exposed us to the equation f(x) = AsinB(x-C) + D. He taught us what A, B, and D did to the sine graph but told us that we’ll learn what B does in gr.12 precal. Now, after over a year of waiting, I found out what B meant and that became my moment of clarity. B stretches/shrinks the graph horizontally.

I also liked how Mr.K did his 1st class on the 1st day of school because I remembered it as inspiring.

I also liked the helpful advice Mr.K said to one of his students: Remember folks, Mr.K says, “If you don’t memorized the unit circle, you will fail.”

By the way, does anyone know how to do Exercise 2 #15?

If f (x) = 2x + 3, find k so that f(k+2) = k + f(k).

2(k+2) + 3 = k + 2k + 3
2k + 7 = 3k + 3
4 = k

...which doesn't make sense to me.

Also, one of our questions in our homework asked us to graph the tangent function. We weren't taught that.

m@rk said...

Zeph,

Question #15 on exercise 2 is just simply using function notation. Since f (x) = 2x + 3 and you have to find k so that f(k+2) = k + f(k).
so we`ll work on the right side first, all you have to do is just substitute k+2 to x so you have:
2(k+2) + 3

On the other side since k is just a constant you just leave it and then again reading the function notation you need to substitute k to x so you have this:
k+ 2(K)+3

Therefore, you will end up with this kind of equation:
2(k+2) + 3 = k + 2k + 3

Then with the help of some algebra you will get this answer:
2k + 7 = 3k + 3
4 = k

-mark

m@rk said...

Zeph,

As for your other question. The graph of the tangent function can be viewed here: http://fooplot.com/index.php?q0=tan(x)

The tangent function has some cool properties. It has an amplitude of undefined, a period of pi and y intercept of zero.

I have so much more to say but i don`t want to spoil the fun.

-mark

zeph said...

lol m@rk .. of course YOU would know.

zeph said...

'moment of clarity' btw