VCE General & Further Maths Question Thread!

[saba.ay]

Can past students give some tips on how to minimise mistakes in Graphs & Relations?

I find it quite straightforward, but it is easy to slip up in linear programming (especially when writing the constraints). Any suggestions to address this issue?

Well, I don't know how effective this will be for you, but whenever the question provided information in worded form and asked us to create a constraint, I would check my answer by substituting random values to make sure that the constraint was right.

eg. 2012 Exam 1: Graphs and Relations q 8
at least 5 loves of white bread will be made for ever loaf of brown bread that is made
 
w= white bread made per day
b= brown bread made per day

I'd first write up my constrain: w ≥ 5b
I'd then check this by subbing in random values for b. So, if I made 1 brown bread, I'd made 5 white bread. If this matches the constraint they provided originally in words, you'd know you have the right answer.

Hope that makes sense.

[Yacoubb]

I have my first SAC this Wednesday (my school divides the CORE Sac into Univariate and Bivariate data). Does anyone have any tips for the univariate section?

[Stick]

Well, I don't know how effective this will be for you, but whenever the question provided information in worded form and asked us to create a constraint, I would check my answer by substituting random values to make sure that the constraint was right.

eg. 2012 Exam 1: Graphs and Relations q 8
at least 5 loves of white bread will be made for ever loaf of brown bread that is made
 
w= white bread made per day
b= brown bread made per day

I'd first write up my constrain: w ≥ 5b
I'd then check this by subbing in random values for b. So, if I made 1 brown bread, I'd made 5 white bread. If this matches the constraint they provided originally in words, you'd know you have the right answer.

Hope that makes sense.

Yes, heaps of kids get these wrong! If you can get your head around this, you're looking really good.

I have my first SAC this Wednesday (my school divides the CORE Sac into Univariate and Bivariate data). Does anyone have any tips for the univariate section?

Knowing you, you probably just need to slow down and read each question carefully.

[Yacoubb]

LOL Knowing me? hehe what do you mean, do I jump the gun?! :p

[Stick]

No, you've probably covered every single little thing in univariate data really thoroughly (just like I did). So now, just relax and make sure you don't do something stupid in your first SAC (just like I did).

[Yacoubb]

No, you've probably covered every single little thing in univariate data really thoroughly (just like I did). So now, just relax and make sure you don't do something stupid in your first SAC (just like I did).

yeah that's what I'm going to focus on in the coming days. Reading some notes and flicking through my bound reference, more or less looking at the most effective approach to questions, Random Sampling,etc, etc. Eh, I hope I do well. Thanks Stick!

[Stick]

Random sampling hardly ever comes up. Might be something to watch out for though!

[Yacoubb]

Random sampling hardly ever comes up. Might be something to watch out for though!

Our SAC for Univariate Data is primarily based on choosing a random sample and using those 24 randomly selected values to find mean, median, mode, IQR, range, standard deviation, boxplots/histogram, write a report. You also have to know why selecting a random sample is important, and show the teacher how you went about doing that I don't think its a major aspect when we come to the bivariate data component for our next SAC.

[abcdqdxD]

When graphing linear inequations on the CAS, is it possible to make the non-required region shaded, instead of having the required region shaded?

[b^3]

Flip the inequality sign.

[abcdqdxD]

In graphs and relations, some questions ask you to deduce the form of the equation, i.e. y=kx^2

Problem is that for some equations, plotting a linear regression line, y against 1/x and y against x^2 looks EXTREMELY similar, i.e. they both look like they have a straight line, but one is not completely straight (but you can't tell if its due to the the pixel limitations of the CAS or it's actually not linear)

Is there another way to check whether the graph is linear other than observation through the CAS?

[Professor Polonsky]

Not sure why that would happen - the rate of change for a y=kx^2 graph would be increasing - i.e. the differences between the y-values will be getting bigger. The opposite should happen with y=k/x.

[abcdqdxD]

Hi,

For linear programming when you're asked to find the point that gives maximum profit within the feasible area, and none of the extreme points actually give maximum profit, how can you identify this?

I'm referring to VCAA Exam 2 2009 question 4 on Graphs and relations.

Thanks

[b^3]

The extreme points don't fit the situation in this case, since you can't have half a flight for the situation. So in that case you would test the integer values that lie inside the feasible region and test which of those gives a maximum instead. Always check if what you're trying and the answer result you obtain fits the situation given

[abcdqdxD]

Is it safe to say that the intersection will always give the maximum value in any objective function assuming decimals are accepted?