## Friday, February 13, 2009

### Happy Valentine's (Approximation) Day! >:D

Hello there mon internet (stalker) classmates! It's ANNabanana here! Right now I am very tempted to say that all we did today in class was math.

>:D

Anywho, we started off the day with a little mental math. You know, the unit circle stuff our mental math's have been based on all week (click here if you need some practice with it). Then we went into small groups so our brain waves could be shared to solve the problems that were on the smartboard. If you would dare to look at Mr. K's slides you'll see what problems I'm talking about. Rather simple trigometric functions, it's just that I have to point out some things to you mon dearies. :D

I'd like you're eyes to be entranced by the slide directly below this.

You see that big red X? Well Mr. K showed us the wrong way to solve equations. Never ever ever EVER divide by a variable because you don't know the value of it and might potentially be zero. When you divide by zero the answer becomes undefined and you don't want that! Talking about undefined...

Why would I point this out? Because I had such a wonderful time writing out the (wrong xD) answers on the slide it was from. No, actually Mr. K pointed out that on our exam we have to write the answers that don't work or that are undefined seperate from the answers that DO work. Also, for those of you wondering why cos x = 2 is undefined, it's because the unit circle has a radius of one and the maximum unit that it can go up to is one. Two unfortunetly is too big. D=

Here's something new. Let's look for the answer in the domain of.. what's this! The set of real numbers?! Oh my! There are infinite answers for this question! How can we possibly write them all down?!?
It all comes down to k. A number in the set of intergers. Something that tells you how many times it goes round and round (with pi). For any tangent say that the answer is (tan x) + k(pi) because every tangent is an unit of pi (half a circle) away from eachother. For all other answers it should be (your answer here) + 2k(pi) because it's going to take one whole revolution around the unit circle to reach that answer again.

The homework for the weekend is the rest of exercise 5 and the last 10 quesitons on exercise 6.

LOL, look what I found on youtube.

Hmmmm... let's see. The next scribe is Mary. :D

"Insert math quote here"

1. Nice post Ann!! I like the youtube video and that mental math help thing. :p

2. LOL at the youtube video. That was great! lol. just one question. Near the end in the last paragraph, aren't the two answers for tangent always one pi length apart and not one radian? or did i just interpret that wrong?

3. P.J. isnt a radian = to one pi? :)

4. gahh i forgot about ex.6! thanks for the post Ann!
i'll do my best as the next scribe, but i am up against the unit circle song..XD

5. ahha sorry ann, they are not equal to each other. there are 2pi radians in a full revolution, meaning there are 6.28 blah blah radians in a full revolution.

6. This comment has been removed by the author.

7. Lol, the vid was awesome. Good job ann.