VCE General & Further Maths Question Thread!

[Damoz.G]

haha damn you couldnt post the pic, what ya needa do is to go on tinypic through google and upload the photo and then just use the IMG link after you upload it and copy and paste it here, i have a few more pics to upload as i am struggling them with aswell lol.

thanks bro

YAY! It works. Let me know if you have a question about my Diagram. It's really rough, so hopefully you can still read it.

[Damoz.G]

hehe, ive got another question when drawing a network, from a Matrix representation, are you allowed to have edges crossing each other when drawing it out,

 I have B->M thats one edges then it goes P->K which looks like a big X, is this allowed, i thought edges were not allowed to cross when drawing out networks?, because if they are allowed to cross i am gonna be pissed thinking all this time you were not allowed too

Yes you are allowed to have the Edges crossing over each other, but make sure that its clearly shown where each line is connecting with the Vertices

[tcstudent]

Wat the heck?, i was so convinced they were not allowed to cross and i didnt even know you were allowed to hack Vertices 2 go around 3 and end up joining to 4, this is why i had so much difficulty with this module, omfg omfg.

[Damoz.G]

Wat the heck?, i was so convinced they were not allowed to cross and i didnt even know you were allowed to hack Vertices 2 go around 3 and end up joining to 4, this is why i had so much difficulty with this module, omfg omfg.

HAHA! Fair enough.

You are allowed to cross over and go around Vertices. The setup of your diagram doesn't matter, as long as all the information is presented and can easily be followed.

[plato]

Hi if someone can help me to understand the answers and how to get there for the following questions from the VCAA exam, I'd be extremely grateful. The worked solutions are on Itute by the way. I know I'm going to look like an idiot since I've got a long list of what I don't understand but I think it's better to ask than just keep quiet so no judging. hahah. (I'm an arts kid so anything maths related is not my forte.)

VCAA 2010 Exam 1

Geo & Trig
Question 6 I got the first part 7.106 but I don't get how  they got the value for TM.
Draw a triangle DTM where DT = 7.106 and DM = 5.5 since M is the midpoint of DC which is 11 long. Now, if you can calculate the angle TDM, you could use the cosine rule on triangle DTM.
Angle ATM + Angle ADT = 90 degrees. So, if you calculate the angle ADT using tan(ADT) = , you can then find Angle TDM and hence the length of side TM.


Question 7 I didn't know how to solve this. I think it was because I was looking for another measurement. Can someone explain how they got 38.8 degrees?
Angle CBD is on the right triangle CBD where CD id the side opposite angle CBD and CB is the adjacent side. Therefore you could use tan(angle CBD) = .
To do this, you must calculate the length BC from the right triangle ABC using the given angle and the given length AB.

Question 9 Why is the volume of water in the cylinder equal to the volume of water in the cone?
When full, the volume of water in the cylinder = where r = 30 and h = 24. This gives a volume of 22619.46…
If this is water is all poured into the cylinder, the water will reach a certain height, assuming that the cylinder is high enough and the water does not overflow. Use the formula for the volume of a cylinder to find the depth (or height) of water. Since you know the values of V, r and , solve the resulting equation.

Question 8 in graphs in relations I forgot how to do this. Can someone refresh my mind?
Let’s use a letter “w” replace for the time being. You can then think of the equation being like .
If we were to draw a graph of , we would have a vertical axis labeled “y” and a horizontal axis labeled “w”. On such a graph, if “y” = 27, then “w” would equal 9.
So look for such a graph among the five present, remembering that “w” really stands for . The graphs A, B, C and D all have (or “w”) on the horizontal axis but only graph A has a point where “y” = 27 when “w” or = 9.


VCAA 2011 Exam 1

Geo & Trig

Question 7 Why is QC double PB? Is there any other method of solving this? Would similar triangles work?
Triangles AQC and APB are similar. Since the length AC in the larger triangle is double the length of the corresponding side AB in the smaller triangle, then all lengths in the larger triangle will be double the corresponding length in the smaller triangle.

Question 8 Why is x/0.8? I know the addition part but I don't know how they got 0.5818.
You need to first identify similar TRIANGLES rather than similar trapeziums. Do this by taking a horizontal line from P across to cross the line TU at a point we’ll call V and then continue to meet the line TU at right angles at a point we’ll call W. You now have two similar triangles PVU and PXS to which you can apply similar triangle ratios. You cannot apply such ratios to similar trapeziums.

Question 9 Again I thought that I needed another measurement. Didn't think it was similar triangles. How did they conclude that?
Angles ABD and ACB are equal. Both triangles ABD and ACB share the same angle at point A. Since these two triangles have a pair of equal angles, then they must have all three angles equal and the triangles must similar. It is now a matter of seeing that side BD = 24cm on triangle ABD is opposite to angle A and must correspond with side BC = 40cm on triangle ABC.
Therefore, each side of larger triangle is times larger than the corresponding side of the small triangle and its area must be times that of the smaller one.

Question 9 in graphs and relations Why is it 5x-5y? Why does it have to be the same gradient as AB? How do you work the gradient for this?
It is not 5x-5y .
The answer is (E) M = 5x + 5y. This line will have the same gradient as AB with a gradient of -1.
By rearrangement,  M – 5x = 5y and so which is a straight line with a gradient of -1 and a y intercept of . We need the maximum value of (greatest y-intercept of a line that touches any and all points of the feasible region along the line AB.

Finally if you have any suggestions on how I can understand questions better, feel free to shoot them at me. (:
Practice, practice and practice. Not only in doing many questions but trying to figure out how what you have learnt can relate to the question at hand.

[Conic]

You need to first identify similar TRIANGLES rather than similar trapeziums. Do this by taking a horizontal line from P across to cross the line TU at a point we’ll call V and then continue to meet the line TU at right angles at a point we’ll call W. You now have two similar triangles PVU and PXS to which you can apply similar triangle ratios. You cannot apply such ratios to similar trapeziums.

You can't use the trapeziums because they aren't similar, not because similar trapeziums can't be used. In this case the trapeziums both share the same angles, but the ratios of the sides aren't equal, hence they aren't similar.

[lala1911]

Wat the heck?, i was so convinced they were not allowed to cross and i didnt even know you were allowed to hack Vertices 2 go around 3 and end up joining to 4, this is why i had so much difficulty with this module, omfg omfg.

I feel your frustration.

[Zealous]

Business Maths - Do we round up to keep a situation logical or round down numerically?

For example:
The number of years required for $9,000 to double in value when invested at 6.3% compound interest, where interest is paid monthly is closest to -
A: 8
B: 9
C: 10
D: 11
E: 12

So I chose E. Solving for n in the compound interest formula will give you n=132.374 [months]. Converting this to years will give 11.0312 years. If only 11 years past, there will be slightly less than 18,000 so therefore there has to be 12 years for there to be 18,000.

So, in a VCAA exam, should I be rounding up or down? I know they are written a lot better than a lot of other companies, so how should I go about it logically? (Kilbaha said I was wrong in this particular question, I've had a few Neap like this which I've gotten wrong because they rounded down.)

[Stick]

I think your reasoning is right, and what I used to do last year.

[tcstudent]

Hi Guys, is it possible to get assistance for question 9
please, thank you

[sam.utute]

Business Maths - Do we round up to keep a situation logical or round down numerically?

For example:
The number of years required for $9,000 to double in value when invested at 6.3% compound interest, where interest is paid monthly is closest to -
A: 8
B: 9
C: 10
D: 11
E: 12

So I chose E. Solving for n in the compound interest formula will give you n=132.374 [months]. Converting this to years will give 11.0312 years. If only 11 years past, there will be slightly less than 18,000 so therefore there has to be 12 years for there to be 18,000.

So, in a VCAA exam, should I be rounding up or down? I know they are written a lot better than a lot of other companies, so how should I go about it logically? (Kilbaha said I was wrong in this particular question, I've had a few Neap like this which I've gotten wrong because they rounded down.)

I always rounded up (I'm pretty sure VCAA also expects you to round up).

[Conic]

If you multiply the matrices you get:



so 3a+12=3b+12 and a+6=4-b. You can simplify these to get a+b=-2 and a-b=0, which is B.

[aestheticatar]

Hey,
Hope you guys are having a great break!

This is from NEAP 2006 Exam 2.
I'm stuck on the proceeding questions b & c:

b. It has been determined that the relationship between deficit and week number is non-linear. One of the managers has also stated that a relationship of the form d=kt^2 will not be successful either. Do you agree with this? Give reasons.

c. The same manager believes that the relationship is of the form d=k/t. Plot a straight line to show that this is true and thus determine the value of k. Label the axes.

I don't understand question b. I don't know how to obtain the k value in c. Concise and detailed explanations would be much appreciated.
Thanks in advance! 

[Stick]

B. Plot the deficit against the time squared and see if you get a nice linear result or not.

C. Same method as B (except use the reciprocal of each time number) and use your calculator's regression function to find k.

[abcdqdxD]

Can someone please have a look at q6?

I think the exam/solutions are wrong

There appears to be two correct answers in C and D.

Correct me if I'm wrong