This is a blog for my second semester pre-calculus 30s students. Have a blast!

Friday, April 28, 2006

Consumer / Exp. Growth test results

Hey folks,

The class average for the test was 64%. The marks were very skewed; 8 people received marks from 80% - 100%. 8 people also received marks from 20% - 51%. The other three were somewhere in the middle. Not bad over all, with the most common error being that some people who did not do so well forgot the compound interest formula or just didn't use it when they should have. Have a great weekend and see you on Monday, where we begin our unit on Logic & Proof.


I forget why I have to do this again, but it seems we get marks for it. So heres my before test post. I didn't know consumer work would involve so much work and understanding. Probably the unit with the most writing in it in my opinion. But its been straight forward so far hasn't it? Well not for me.. Good luck today on the test. ( I prayed this morning and asked if I could pass of the test haha )


I need help... This thing is driving me nuts... well the fact that I wasn't able to get the pre test does make me go nuts...

Is it Gross Income- Union Dues= Taxable Income??

Well that's all i need to ask since that's the only thing that's messing me up...


Have a great day guys

Thursday, April 27, 2006

Consumer / Exponential Growth Pre-test answers

Part I - Short Answer:

1) $1788.46

2) $209.70

3) $7919.36

4) $2576.92

5) $1123.75

6) $423.50

7) a) $473.12 b) $1178.89

8) $11.00 / hr

9) $12916.42

10) $700.00

11) $1300.00

12) $25.90

13) $41.42

14) $1664.00

Part II - Group Problem Solving:

1) $129.57

2) $1722.36

3) a) $2220.37 b) $2228.92 c) $2233.30 d) $2236.25 for the estimated budget you're just trying to end up with some money left at the end of the month and making sure everyting is in the right place.

*** One more thing folks, exponential growth will also be covered on the test, so be sure to be comfortable with that. Good luck!!!! If you haven't made your post yet, you should do it now if you want your mark on the test. If you have no idea what I'm talking about then scroll down and read my post on the last test results.


I just have a question on the take home unit.

Do you have to hand anything in or show Mr. Malandrakis any of the work that we did??

Well..ya thats all i wanna know, and does this post count for my mark? Haha.


this is nothing just seeing if im doing this right.

Wednesday, April 26, 2006

Yeah another pointless post

Consumer Math, I never thought I'd find another type of math that I'd have problems with but apparently I was wrong. It's not that I don't understand it I simply find it frustrating when I get confused half-way through and suddenly lose track of where I was going with a question.......I am doomed when Friday rolls by.

Post haha

Hey guys! To be honest, I'm having trouble with consumer?! haha. I don't know why. Probably because I don't like reading. It's embarrassing I can't do consumer and I can do pre-cal. HAHA! As Carla said, we did consumer booklet today. I forgot mine so I had to share with John. I was supposed to be the scribe for today but there's nothing really to scribe for. No lesson... no exercise review either since most of us understand Interest. Well, it is pretty easy. Property tax confused me however. Budgeting takes a long time. I'll never want to be a parent! Geez. Okay... I'm done. See you tomorrow!


This isn't really a scribe post. Lol. That's what Mr. Malandrakis said. I can just post. So here. This won't really make sense.

I've taken Consumer Math before, so i'm hoping that i'll be able to ace the test. But i'll still study.

We did the Consumer Math booklet today.

I think i'm having problem with the conversion. I'll just ask Mr. Malandrakis tomorrow.

So, that's it. I told you this is nothing.

Tuesday, April 25, 2006

Scribe =\

Well it seems I'm the scribe =\, I thought I already went this cycle.. oh well.

Today, we did some learning ..

Simple Interest Formula:
i = prt , where..

i is interest
p is principal (starting amount?)
r is rate
t is time

Another formula to remember is..
Amount = principal + interest

Compound Interest formula:
A (amount) = P(1 + r)n

Revised formula:
A = P(1 + r/s )ns

Well, sorry that this scribe post is soo short and relatively late. I totally forgot that I was scribe today.. grr John. lol. Well I have no clue who to pick for tomorrow's scribe.. I guess I'll pick..Vince. :\ sorry

Tonight's homework is Exercise.. ermm I'm just guessing but probably Ex. #44. Also, there is a test on friday.. and mm remember to do your consumer math booklet. T.T gtg do mass ELA homework now..

Monday, April 24, 2006

Scribee Postee

Hey everyone,

I'm going to make this scribe post as short and detailed as possible.


For values to grow exponentially means to increase by a different amount each time.

  • The formula for an exponential growth: f(x) = abx
  • Restrictions for the formula are: a & b R, a 0, b > 1
The simplest exponential function is : f(x) = 2x

ex. The growth of a $7000 RRSP (RRSP means Registered Retired Savings Plan)

Time (years)

Value ($)













i) estimate the time needed to reach $14000. There are several steps:

  1. Press the STAT button in your graphing calculator.
  2. Plot out the Time variables on the L1 column, and the Value variables on the L2 column.(Note: make sure Plot1 is on. You can enable this by going to the Stat Plot menu on your graphing calculator. [2nd func, stat plot, press enter on plot 1, set it on.])
  3. You will now see dots on your calcuator. We must now find the exponential expression. You can do this by pressing the STAT button your graphing calculator, going the to the CALC menu, pressing 0 or finding the ExpReg on the categories. Press ENTER twice.
  4. To plot it as an equation on the Y= menu, go to Y= menu, press VARS, then press 5 or pressing ENTER on the Statistics selection. Then go to the EQ menu, select option 1 (RegEQ). You should now have the equation on your Y= menu. Now you can graph it and find the solution to the problem.
Doing this, you should have 8 years as an answer.

ii) Find the value of the RRSP after 12 years:
You might want to change your window settings for this one. Set the Xmax value on your graphing calculator to 15. You should get $19630.28 as an answer.

NO HW for today except for that worksheet we finished in class.

Next scribe is Tim-Math-y.

Sunday, April 23, 2006

Circle Geometry class average

Hey folks,

The class average for the test was 70%, on the button. A job well done and this was not exactly a "walk in the park" test if you know what I mean. Starting next unit, being tomorrow, which will be only a few days discussing some consumer math topics along with exponential equations, we are going back to the daily scribe routine. I noticed that we kind of haulted it during the circle geometry unit and that's ok, but this time it will be worth one mark on your next test, being on Friday. This means that EVERYONE must contribute at least one POST before Friday's test in order to receive this one mark. As the final exam is just around the corner, it will become more and more important to have multiple sources of review for different topics that are covered in class. Make sure you share this with anyone else in the class that you think has not read the blog in a few days.

Thursday, April 20, 2006

Pre-test corrections

Hey folks,

Sorry for the inconvinience but there are a few corrections on the pre-test answers. I was in a rush this morning and I quickly posted the answer key that was provided to me from the teacher that gave me the test. Unfortunately there was a few errors. Thanks to Vince and his time and efforts those errors have been corrected. Please take a look at his comment that he left me on the answers for an update. Thanks again to Vince. Good job!!!

Circle Geo. pre-test answers


1) d 2) b 3) c 4) b 5) b 6) d 7) a 8) c 9) b 10) b


1) ABC is an impossible triangle, so no solution.

2) Using the pythagorean thm... OE = 4.9

3) vertex = (2, 4)
eq'n of line in std form: x - y = 0

distance = sqt(2) / 2

4) angle 5 = 45 deg (insc. angle subtented by same arc)

angle 1 = 180 - 45 - 75 = 60 deg

angle 2 = 35 deg (insc. angle subtended by same arc)

angle 4 = 180 - 45 - 60 - 35 = 40 deg (opp. angles of cyclic quad supp.)

angle 3 = 180 - 75 = 105 deg (opp. anles of cyclic quad supp.)

5) angle 1 = 15 deg (cong. triangles - SSS)

angle 2 = 180 - 15 - 90 = 75 deg (tang/chord thm)

angle 3 = 90 - 75 = 15 deg

angle 4 = 180 - 90 - 15 = 75 deg

angle 5 = 90 deg (tang/chord thm)

6) angle 2 = 180 deg (subtended by diam.)

arc AD = 60 deg

therefore...angle 1 = 110 / 2 = 55 deg (central / insc. angle subtended by same arc)

angle 3 = 60 / 2 = 30 deg (insc. angle subtended by same arc)

arc BC = 180 - 60 - 50 = 70 deg

therefore...angle 4 = 120 / 2 = 60 deg (insc. angle subtended by same arc)

angle 5 = 70 deg (cent. angle subtended by same diam.)

7) using pythagorean thm.... OD = 5.29 cm



Friday, April 07, 2006

Test #4 Results

Hey folks,

The tests are marked and the class average is 61%. I realize that some of you might be dissapointed because this means no ice cream in June (for the time being...until the next test). I want you guys to understand a couple of things. First of all this is a very tough, intense, and challenging unit, arguably the toughest of the course. Given that and the fact that we flew through this week covering 5 days of work in only 4 days, a 61% class average is still impressive for the nature of this course. The class average, as a whole for the course so far, is 67%, which is on pace to achieve one of the highest class averages in a pre-cal class (any grade level) in this school in a while. The quality of work I'm seeing from most of you is still extremely impressive and I'm very proud.
Here's another interesting fact, not fiction. The current pass rate for pre-cal students in this school is 63%. This means that in any given pre-cal class in any grade 63% of students, on average, will pass the class. In our class we have 21 students and 17 are currently passing. That's an 81% pass rate, which is unreal. Here's an even more amazing fact. Three of the four students who not passing this course (at the current time) have marks between 46% - 49%, which means we have the potential to have over a 94% pass rate in this class, with a small chance as well of everyone in the class passnig, after the exam of course. Just to let you know, to my knowledge, there has never been a math class (pre-cal, consumer, or applied) in any grade in recent history where everyone passed. This goal is within your reach. We'll talk about this more next week. Enjoy the gorgeous weather this weekend.

Thursday, April 06, 2006

Analytic Geometry test outline

  • Know how to determine the center and radius of a circle given its equation in expanded form.
  • Know how to determine if a given point is a solution to a system of equations
  • Know how to find the solutions, graphically, to a system of linear / non-linear equations using your TI-83.
  • Know how to solve a 2 x 2 or a 3 x 3 system of equations algebraically given a straight question or a word problem where you might have to set up a system of equations, like your worksheet.
  • Know how to solve non-linear inequalities: quadratic, rational, absolute value...algebraically and understand that to solve these inequalities means to leave your answer in interval notation unless asked to express as a number line.
  • Know how to graph a system of linear inequalities using your TI-83.

Wednesday, April 05, 2006

Yesshterrday's Scribe!

Hey guys. So I was the scribe yesterday but I just had the chance to do it today because of some internet problem I had on my computer yesterday. But anyway, here's my post..

Systems of Non-Linear Equations

[+] CONIC is a word that describes a graph that has a 2nd-degree equation.
-> These are some examples of Conics:

[+] A QUADRATIC-LINEAR system refers to the equation of one conic & a line.
-> A Quadratic-linear system can have:

-> Consider:

Ex): Solve:

-> A Quadratic-quadratic system can have:

Ex): Solve:

And that's all guys! I hope that my post had refreshed your memory about what we had learn yesterday, and again sorry for the late post.
OH yeah before I forget! Don't forget to do our Analytic Geometry Pre-test oryt guys (:

Fill-in scribe

Hey folks,

Jamilyn, who was supposed to be the scribe the last couple of nights, has had some computer trouble. I know it's after spring break and all but let's please stick with the "fill-in scribe" routine because as you can see some of these lessons during class are getting quite detailed and some of our classmates might be in need of some extra assistance or a refresher.

Post: Graphing Inequalities

Equations without an equal sign is an inequality...

An inequality only has a > (greater than), < [less than], [greater than or equal to], and ≤ [less than or equal to] sign...

a graph of an inequality does NOT appear as a line...

if it has the greater than sign.. it means that all the values above the line is your solution...

if it is less than.. all values at the bottom of the line is your solution..

REMINDER!!!: The solutions for these do not include the points of your line... so the line you graph should be a broken line

if it is greater than or equal to, or less than or equal to same rules apply but the line of the graph becomes solid

AND- Intersection

OR- Union Intersection...

it is where the two graphs both have the same points for their solutions Union- all possible solutions for both graphs


Step 1: Enter the two points...
/Y1= x
/Y2= -x

Step 2: Put your cursor in the first character(** the slash thing) and press enter...
/ <-- I mean this one... it should look like a right triangle... one with the right triangle below means less than... one with the right triangle above means greater than... EX: y≤ x AND y≤ -x

Gray part and the Black part is the solutions for y= x and y= -x or the UNION...

The Black part is the INTERSECTION...

For QuAdRaTiC FuNcTiOnS...


y≤ x2

I am not quite sure about this since i didn't understand it that well...

So the next scribe is.........




Answer key for analytic geometry pre-test

Part I - MC:

1) a 2) c 3) d 4) d 5) c 6) b 7) c 8) a


1) using distance formula... r = 5.8

2) using substitution, elimination or graphing and finding the pt of intersection on your calculator
sol'n: (-4, -11)

3) 1 solution (as seen by graphing circle and straight line)

4) using distance (from pt to line) formula... d = 5 (root 13) / 13...(sorry about the lack of mathematical symbols, I never had a chance to download the software that produces them.


1) Graph all lines on paper and find all 4 vertices (2 are y-intercepts, the other two are points
of intersection.
You must then find the equation of each diagonal line (using pt-slope formula from S2)...
The equations of the diagonals are: y = x - 2 and y = -(5/6)x + 4.
The point of intersection of these two diagonals is (3.3, 1.3).

2) You substitute all three points, (10, 1500), (20, 2000) and (30, 1500) into the equation and
you end up with the following 3 x 3 system:

1) 100a + 10b + c = 1500
2) 400a + 20b + c = 2000
3) 900a + 30b + c = 1500

2) - 1): 300a + 10b = 500 4)
2) - 3): -500a - 10b = 500 5)
4) + 5): -200a = 1000

...therefore a = -5

....after more substitution... b = 200, c = 0

...therefore sol'n = (-5, 200, 0)

.... h(t) = -5t^2 +200t