Wednesday, February 18, 2009

BOB - as it was called in past years

Hey everyone ! Allow me to preface this post by saying that this is a very good class and Mr. K. has an exceptional way of teaching. I understand that one should create a blog post prior to Circular Functions Test, so I just wanted to create mine now since all yall can read this stuff one day earlier rather than just the day before the actual test.

Anyways, this unit is almost over and I'm confident. At my first encounter with this unit, I was appalled and just disgusted, which is way of saying “Oh my gosh! How am I supposed to do this?!?” This was last summer though, so I immediately gave up. I actually tried being diligent back then, and now, I plan to remain diligent.

Anyways, comprehending the unit circle was not such a laborious task to me. The pattern is very self-evident. Mr. K. had helped elucidate several math concepts. Nevertheless, I do have the propensity to make silly mistakes. Other than that, I am fairly prepared, but I am still going to study to ensure that I am at my best.

So here are some things that hopefully aid you on the test. In addition, I know that this is basic mathematics and is common sense, but people get stressed out and forget the easiest things, which consequentially leads to mistakes. So these are my efforts to help.

Area of Circle = πr^2
Circumference of a Circle = 2πr, πd

When the denominator is zero, the answer is undefined. For example, Tan(π/2)= 1/0 , therefore, undefined. Another example is Csc(π) = 1/sin(π) = 1/0, therefore undefined.

Remember that Mr. K wants your work to be written in a vertical manner and that if there is no solution or the answer is undefined, state it.

When obtaining the square root, two values can be achieved. The square root of 4 = ±2. Do not forget that. Another example is R^2 = S + T. Therefore R = ± squareroot of (S + T) .

Here is another common mistake. (sin x)(tan x) = (sin x) A rational thing to do would be to isolate tan(x) to equal 1. However, that only obtains a partial bit of the actual answer. What you do is transpose sin(x) from the right side to the left side. After that, you factor out sin(x) which results in sinx(tanx – 1) = 0.

Cosx and sinx has a range of [-1,1] . Anything less than -1 or greater than 1 leads to "undefined"

DABC – mnemonic for parameters

Round to a minimum of 4 decimal places yall when necessary.

If you finished all of your exercises, review them. If you didn't finish them, go do them!

Check out some Youtube videos, past Precal Blogs, other websites, that online course website (merlin), and PC40s Mb site.

Good luck and ask questions if you have any problems.


  1. Hey man, you made a slight error
    you listed the area of a circle 2pi(r)
    should it not be pi(r^2)?