Things to look out for in the exams

[astone788]

Odd. The whole entire year I've been taught that 'correct' implies no rounding. Even today I double checked this with my teacher and he reaffirmed what I beleived. He looked me dead straight in the eye unwavingly. There was no way he was joking.  I don't know what to do now. Gotta trust my teacher. But If I fail the exam based on rounding I wont be happy. 

[brenden]

Odd. The whole entire year I've been taught that 'correct' implies no rounding. Even today I double checked this with my teacher and he reaffirmed what I beleived. He looked me dead straight in the eye unwavingly. There was no way he was joking.  I don't know what to do now. Gotta trust my teacher. But If I fail the exam based on rounding I wont be happy. 

Show all your working out and you'll only lose one mark for a rounding error no many how many you make is what I've been told.
I also strongly reaffirm what Yendall and 99 have said. If VCAA had made a mistake they would have corrected it by now. Correcting essentially means rounding. Trust your teacher if that's what you want to do, just show all your working out so you only lose one mark.
I also think it's acceptable for you to write 13.769 because that's technically correct to two decimal places. My teacher has been an examiner for a while and that's how he marks papers, but he's an over technical man so I'm going to just make sure I round correctly in case.

[TheRajinator]

If you are doing a maximum/minimum problem for linear programming, and the co-ordinates of the vertices are not integers, but the problem requires them to be, you use the sliding line method to find out the maximum or minimum objective function values.

To do it, you must graph your objective function as a dotted line in red pen.  (Say if it's 2x+3y then just put a random value as your y-intercept, so you'd graph something like 2x+3y=6).

Then, grab your ruler and slide from the bottom to the top of your page if the gradient of the objective function is positive, and top to bottom if the gradient is negative.  (Whilst keeping the same slope as the objective function you've graphed)

The first point you hit is the minimum value, the last point you hit is the maximum value, and you can sub the last point that works into the objective function to get the maximum or minimum.

Hey my class didn't do Graphs and relations as a module so I never learnt this. I kind of still don't get it, how would you apply this to Q4 on the VCAA 2009 exam 2? I don't get what you mean when you say "grab your ruler and slide from the bottom to the top of your page if the gradient of the objective function is positive, and top to bottom if the gradient is negative." Thanks 

[Teachers_Pet]

Hey my class didn't do Graphs and relations as a module so I never learnt this. I kind of still don't get it, how would you apply this to Q4 on the VCAA 2009 exam 2? I don't get what you mean when you say "grab your ruler and slide from the bottom to the top of your page if the gradient of the objective function is positive, and top to bottom if the gradient is negative." Thanks 

If you Just insert the x and y values to the vertices (10,0) , (4.5,5.5) and (0,8) (not accurate coordinates)  into the equation P=1200x+1300y and take the highest value. Although this question doesn't ask it you should be able to interpret your answer and understand what it means e.g the number of flights and no. of crew to achieve this maximum profit

[ashoni]

You could add the concept behind the scale factors, k, for geometry and trigonometry. These questions can get confusing for some students, especially when a question has the volume(k^3) or area(k^2) factors instead of the length factor (k).

[calcalcal30]

Transforming Data Using Lists and Spreadsheets & Data and Statistics:
Add lists and spreadsheets and enter all appropriate formulas into seperate columns. I have saved mine as a document, this is what it looks like:

What happens when you do control+n to clear memory so you can store matrices etc. This would be deleted wouldn't it?

[panicatthelunchbar]

Just clarifying some matrices: when we r given A(0) - initial state matrix, we use A(10) = T^10 * A(0)

but if we are given A(1) as an initial....we use A(10) = T^9 * A(1)

[Yendall]

Just clarifying some matrices: when we r given A(0) - initial state matrix, we use A(10) = T^10 * A(0)

but if we are given A(1) as an initial....we use A(10) = T^9 * A(1)

If you're given A(1), I'm not sure whether that would work. You could try it out I guess.

Say the inital state matrix is:

The transition matrix is:



If the initial state is  



So yes, it works.

[panicatthelunchbar]

that makes sense, thanks!

so if they give u an initial say what u gave above, then they said that for example thursday is the first day....then thursday would become that initial? this was on mav 2010

[Yendall]

that makes sense, thanks!

so if they give u an initial say what u gave above, then they said that for example thursday is the first day....then thursday would become that initial? this was on mav 2010

It would depend on the context, but essentially yes. If Thursday is depicted as then it will always be the initial state. The problem would then arise in interpretation, as the 5th day would be Tuesday and stuff.

[billyjackson768]

Things to look out for...? I say ducks. They were where I made my stupidest mistake on the 2011 VCAA exam 2 (in matrices, last question). I remember doing some stupid things there, in fact I actually even tried to divide a matrix... one of the first things you're taught not to do when you start doing them in year 10. In fact I'm going to print out that question and attempt it now before adding to my summary.

[shmootz]

I know it's a day before the exam... but I just saw this post now

What is the best way to do this?:

Module 5: Networks and Decision Mathematics
- Determining a critical path from a table of values

I was taught to draw out the whole network diagram, but it sounds like it would be a royal waste of time.

Thanks!

[Yendall]

I know it's a day before the exam... but I just saw this post now

What is the best way to do this?:

Module 5: Networks and Decision Mathematics
- Determining a critical path from a table of values

I was taught to draw out the whole network diagram, but it sounds like it would be a royal waste of time.

Thanks!

It depends on the complexity of the table. It doesn't take too long to draw it out, but if you can picture the network in your head then I guess you could do it mentally.

[Yendall]

Transforming Data Using Lists and Spreadsheets & Data and Statistics:
Add lists and spreadsheets and enter all appropriate formulas into seperate columns. I have saved mine as a document, this is what it looks like:

What happens when you do control+n to clear memory so you can store matrices etc. This would be deleted wouldn't it?

Save it as a document so you can delete the page, but restore it later for further use.

[TheRajinator]

Just clarifying some matrices: when we r given A(0) - initial state matrix, we use A(10) = T^10 * A(0)

but if we are given A(1) as an initial....we use A(10) = T^9 * A(1)

If you're given A(1), I'm not sure whether that would work. You could try it out I guess.

Say the inital state matrix is:

The transition matrix is:



If the initial state is  



So yes, it works.

Is that always the case? In MAV 2007 exam 2 Matricies Q4,b,c they give us I₀ and in the solution when they ask for 5th week they use T^4*I₀ instead of T^5*I₀. Also if they give us an intial state matrix, say S₂ does that mean to find S₄=T^4-2*S₂ therefore S₄=T^2*S₂