VCE General & Further Maths Question Thread!

[BLACKCATT]

When we are asked for a difference equation, how do we know when the initial value is t1, or t0?
For example

for this question i got, t(n+1)=0.95(tn)+30,000 t0=200,000

[wholeT]

For exam 2, is it required to show full workings + full worded sentences?

[Zealous]

When we are asked for a difference equation, how do we know when the initial value is t1, or t0?
For example

for this question i got, t(n+1)=0.95(tn)+30,000 t0=200,000

Pretty much I find the given information is the start of a sequence (like the first week, or first hour) then it will be t1. If the information gives information before a sequence takes place (like "initially" or "at the start") then it will be t0 - so in the question you showed, I would use t0.
Have a look at what I wrote here a few months ago:

Spoiler

Just expanding on what Horacio said:
I like to just write down next to the question if the term they are giving you is like the first term of the sequence or the initial term before the sequence starts.

For example, from a VCAA exam a question was:

"A crystal measured 12cm in length at the beginning of a chemistry experiment. Each day it increased in length by 3%, the length after 14 days of growth is?"

I write down that initally the length is 12cm before any days have past, so the equation will be:

Spoiler

Personally for this question, I wrote next to the question "after 1 day of growth, it will 12.36".

as you want the growth to happen 14 times (after 14 days), so in this case you don't use "n-1" as the 12cm is like the initial term before the first day of growth.


An example of the case in which you use "n-1" is:

"In the first month, the gardeners worked 625 hours. In the second month, the gardeners worked 500 hours. How many hours did they work in the fifth month.

Now we know the first term of the sequence is 625, so we have to use "n-1" or else we will generate a sequence after the first month. I wrote next to the wording there.

Hopefully that made some sense, I get so annoyed by the wording we get in some of the questions like "during", "after", "more". Or the questions when they want you to find how much "n" until one sequence reaches over a certain value.

For exam 2, is it required to show full workings + full worded sentences?

For questions worth more than 1 mark, appropriate working out should be shown. If the question is one mark, then a correct answer will suffice (but working out is always useful).

[lala1911]

When we are asked for a difference equation, how do we know when the initial value is t1, or t0?
For example

for this question i got, t(n+1)=0.95(tn)+30,000 t0=200,000

I get it from reading the question. It's really tricky, especially when they say "at the end of the 8th day", "at the beginning of the 11th day".
I got the same answer as you. I think by 'initially' they mean immediately, before any years have been completed, therefore I think t0 = 200000

[tcstudent]

Hi guys this relates to module 6 - matrices
could i  get a solution to this please.

[KevinooBz]

Hi guys this relates to module 6 - matrices
could i  get a solution to this please.

(Image removed from quote.)

All you need to find is the number of people who are expected to change their votes. 25% of the people who initially plan to vote for Rob say they are going to change their vote and 24% of the people who initially plan to vote for Anna will also change their vote. Rob has 5692 voters initially, but 25% will change and vote for Anna. Anna has 3450 votes initially, but 24% will change and vote for Rob. So in total, the number of people who change their vote is (0.25  x 5692) + (0.24 x 3450) = 2251.

[Cort]

Pretty much I find the given information is the start of a sequence (like the first week, or first hour) then it will be t1. If the information gives information before a sequence takes place (like "initially" or "at the start") then it will be t0 - so in the question you showed, I would use t0.
Have a look at what I wrote here a few months ago:

Spoiler

For questions worth more than 1 mark, appropriate working out should be shown. If the question is one mark, then a correct answer will suffice (but working out is always useful).

Did I mention I love you? I love you. Always been confused with the t0/t1 rubbish, and it's been the crux of where I go paranoid when I do further number patterns. I love you man.

[Yacoubb]

Hey guys

Is anyone going to check their MC answers online on Friday Nov 1 after the exam. I have no idea whether I want to or not. I feel like its going to just kill me if I find I've made a multitude of errors, and ruin it for me, and that if I don't look up the answers, I'm going to CONSTANTLY be worried.

I was thinking of maybe checking one of the exams (possibly checking answers for exam 1). If I do well, it will be a MASSIVE confidence boost for exam 2; it sort of works out both ways.

Inputs would be great

[Cort]

Hey guys

Is anyone going to check their MC answers online on Friday Nov 1 after the exam. I have no idea whether I want to or not. I feel like its going to just kill me if I find I've made a multitude of errors, and ruin it for me, and that if I don't look up the answers, I'm going to CONSTANTLY be worried.

I was thinking of maybe checking one of the exams (possibly checking answers for exam 1). If I do well, it will be a MASSIVE confidence boost for exam 2; it sort of works out both ways.

Inputs would be great

Oh definitely - even if I don't do too well, there's a sense of panic that would give me the motivation to study just a bit more to consolidate knowledge. Negative reaction, you know?

[Damoz.G]

I checked it after completing Exam 1. But the one mistake that one of my friends made, was wasting time circling it on the booklet that you get to keep as well as the MC Sheet at the same time. He should have done the whole exam first, and then copied it out, not at the same time - Otherwise you are wasting time and will not finish. He ended up guessing about 2 or 3 at the end (which isn't too bad), but its still costly marks. =/

So do the whole exam first, and if you have time at the end, then copy it over to your question booklet.

For those wondering how you can mark your Exam 1 (Multiple Choice Exam), the Solutions for each exam will usually be up on iTute on the night of the exam (So on the Friday at night), or within 24 hours of Exam 1 being finished. They are done by teachers, so they COULD also be wrong - Usually not dramatically wrong though.

[Kuchiki]

I checked it after completing Exam 1. But the one mistake that one of my friends made, was wasting time circling it on the booklet that you get to keep as well as the MC Sheet at the same time. He should have done the whole exam first, and then copied it out, not at the same time - Otherwise you are wasting time and will not finish. He ended up guessing about 2 or 3 at the end (which isn't too bad), but its still costly marks. =/

So do the whole exam first, and if you have time at the end, then copy it over to your question booklet.

Hmm, I disagree with this. I think it is best to circle the answers on both the question booklet and the multiple-choice sheet as you go (unless you're neatly and artistically drawing circles in your question booklet, I don't see this as "wasting" much time). And then, at the end, even if you have just a few minutes left, you can quickly go through your question booklet and make sure that your answers match up, because working out the right answer in the question booklet but then accidentally shading in the wrong answer in the multiple-choice sheet would be an awful mistake to make in the exam.

As for the question of whether to check your answers online, I think it really depends on the kind of person you are. I personally didn't do it because knowing any of my mistakes in an exam would have just caused me to dwell on them and distracted me from my later exams, but if you really believe that it would motivate you to do better, then go ahead.

[unfamila]

This is probably a really easy question, but how to you work out the std deviation from a histogram. Do i just count the percentages from around the median up to 68% and take an educated estimate?
For example Q3-  http://www.vcaa.vic.edu.au/Documents/exams/mathematics/2010furmath1-w.pdf
Also in Q2- Looking off the box plot it looks as though the IQR is 2, is there a mathematical approach to getting 2.7
Thank you in advance

[lolipopper]

for question 3. i did it by counting the number of bars till the one in the middle, because it is a normal standard curve, and dividing it by 2. thus two columns represented one STDev. its supposed to be an approximate.

for question 2. the Q3 is 181.5 by observation and Q1 is 179. thus IQR is 2.5. This is why the option of 2.7 is not really close to the other options because again its an approximate.

For both of these until unless you calculate the number of ovens for each temperature (this would also be approximate as y-scale isn't clear), and work out the STDev and IQR through that, i'm not aware of any other method that could be used that is learnt in further maths. 

[Yacoubb]

This is probably a really easy question, but how to you work out the std deviation from a histogram. Do i just count the percentages from around the median up to 68% and take an educated estimate?
For example Q3-  http://www.vcaa.vic.edu.au/Documents/exams/mathematics/2010furmath1-w.pdf
Also in Q2- Looking off the box plot it looks as though the IQR is 2, is there a mathematical approach to getting 2.7
Thank you in advance

Range divided by 6. You see, this method could only be applied if your data distribution was approximately symmetric with no extreme values (or outliers).

[lala1911]

Hello, I have a few questions:

1. Number Patterns
i) For the difference equation tn+1 = 2tn - 1, if t4=5, then t3=       (my answer was 5, just unsure whether it is 1)

2. Networks
i) Would you include dummy activities in part of the critical activity? e.g A - B - C - d1- E
ii) Would you include dummy activities as a predecessor? e.g A - B - d1 - H

Thank you