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## #1 Re: Help Me ! » Mathematical model (Extended modeling and problem solving assignment) » 2011-08-20 22:03:08

Just another quick question I wasn't sure if I should of started a new post or not . . .

Why do we use a cosine graph instead of a sine graph is their a particular reason when talking about daylight hours? Does it even matter which we use because a sine graph is just a shifted version of a cosine graph?

## #2 Re: Help Me ! » Mathematical model (Extended modeling and problem solving assignment) » 2011-08-13 09:57:43

I was given the specific formula by my tutor. I'm not even sure how I would get excel to do that . . . Would it be worth figuring that out and then comparing my formula to that of excel?

Thank you for the help

## #3 Re: Help Me ! » Mathematical model (Extended modeling and problem solving assignment) » 2011-08-12 20:23:35

I'm not sure what you mean . . . I used excel to plot the data and then I just used the longest and shortest days from the collected raw data to find the ampitude (max-min/2) and the midpoint (max+min/2)  and then I just used (B=2*Pi/52) I used 52 as my Period because 52 weeks . . .  and then I just subd those values into my equation to find the model. I put the actual formulas in excel so that it didn't round it.  I just used the right click select data function in exel to add the model to the graph

## #4 Re: Help Me ! » Mathematical model (Extended modeling and problem solving assignment) » 2011-08-11 12:08:35

Yeah we had to do a couple of scatter plots + models ( I attached them to the message)  We were told to do the Mondays simply because some raw data had already been collected for this day in the year 2000.

2000 model - 1.72 * cos(0.121*X) + 12.13     (I don't think I need to fiddle with the C value but I'm not sure)
2010 model - 1.73 * cos(0.121*X) + 12.15

## #5 Re: Help Me ! » Mathematical model (Extended modeling and problem solving assignment) » 2011-08-10 09:42:25

Yeah I forgot about that, it was the monday of every second week. So the sunrise and sunset times for those days

## #6 Help Me ! » Mathematical model (Extended modeling and problem solving assignment) » 2011-08-10 00:53:36

FiggelHorn
Replies: 12

Hey guys and girls

I just started my second semester of year/grade 11. I just recently received my new math assignment.

So basically our task is to analyse the daylight hours in two cities and make recommendations about whether these cities would be able to sustain a solar electricity power plant

We needed to make a couple of graphs and models etc. all of which I have completed without incident. Now I am up to the discussion So the question asks "Explanation of the strengths and limitations of the mathematical model in terms of what the model can/cannot be used for and why"

These are the ones I could think of;
strengths
- Ease of access/dont need to gather a lot of raw data
Limitations
- Cannot predict things such natural disasters, sandstorms etc.
- Very reliant on data ie. if data is wrong the model will be wrong.
- Not 100% accurate
- Cannot predict things such as cloudy days etc . . .

It could be used for large scale predictions such as daylight hours over the period of a year where error of + or - 30 min are not catastrophic but on smaller scales such as on a day to day basis those errors would become apparent . . .

If anybody has any suggestions ie things I could add etc. please let me know I realy want to get into those A's B's are just mediocre

PS If you would like any further information please let me know I wouldn't mind scanning in the task sheet or uploading my graphs etc.

## #7 Re: Guestbook » vote for your fav subjects » 2011-06-05 18:38:31

Chemistry!!  Who doesn't love chemistry!

## #8 Re: Introductions » Hello guys and girls :) » 2011-05-29 01:08:41

There are 4 semesters from year 11 to year 12, each semester is then also divided into two terms. I am currently doing semester 1 term 2, so thats

Exploring Data / Statistics
Indices and Logarithms/ Exponential Functions

I tried to read up on the GCSE but I really couldn't make sence of it all . . .

## #9 Re: Introductions » Hello guys and girls :) » 2011-05-29 00:06:01

Yeah Bob I didn't understand it much when I came here

Math A is like the everyday math, where as math B is like a little harder and then math C is calculus which you have to do in conjunction with math B . . . It's pretty hard to explain I'll add a wiki link that explains it a lot better in the bottom.

http://en.wikipedia.org/wiki/Mathematics_education_in_Australia

## #10 Introductions » Hello guys and girls :) » 2011-05-28 22:11:50

FiggelHorn
Replies: 7

Hey guys

My name is mark I'm currently doing year 11(16 years old) math B, I really enjoy math even though I'm not extremely good at it partially because I missed an entire year moving from South Africa to here (Australia) etc. Not that its an excuse since that is one of the wonderful things about math you can always catch up (just need to put in the effort). But enough with all the sob stories were not on Australia's got talent, I hope to learn as much as possible from this site while still having an extremely good time, I also hope to become an active member in this community giving and taking as much as possible.

## #11 Re: Help Me ! » Home loans (Math B*PRIMARY SCHOOL) » 2011-05-28 21:22:10

Thank you guys for the help, I handed the assignment in just the other day I'll be sure to let you know what result I get.

## #12 Help Me ! » Home loans (Math B*PRIMARY SCHOOL) » 2011-05-21 13:13:07

FiggelHorn
Replies: 4

Okay so I have a math assignment where in I have to type up some spread sheets for my "friend" ect (The details are in the attached pictures I have comleted akk the spreadsheets but now I have to discuss the assumptions I made during the assignment and I can only seem to find one where as some other kids in my class have found 4000 words worth of assumptions. If somebody could just help me find a couple more assumptions then I could finish this hellish assignment! Thank you for your help