VCE General & Further Maths Question Thread!

[Billion]

How do you differentiate between options A and C?
The answer is A, but I chose C as the balance of the loan reaches near 0 assuming that it has been paid off?

Thanks

Edit; also question 3 from the VCAA 2010 exam 1 (MC)
I've never seen a question stated like that before, how exactly do we calculate the standard deviation?

[LiquidPaperz]

it doesnt mention anything along those lines?

so how do you know it reaches 59.99?

[Billion]

it doesnt mention anything along those lines?

so how do you know it reaches 59.99?

I don't.
However the height can reach anywhere up to 59.99, as long as it doesn't reach 60.
So if your cross section has the highest peak above 50m, but below 60m you'll be awarded marks.
It doesn't need to look exactly like the diagram as long as the interval heights are correct and the steepness of the lines are also correct.

[LiquidPaperz]

how did you know it has to be more then 50? the maximum height is 50 isnt it? so it has a somewhat turning point at 50m?

could you response to my earlier comments about why its a straight line? and not a contour line like a concave shape kinda, please/

thanks

[IntelxD]

How do you differentiate between options A and C?
The answer is A, but I chose C as the balance of the loan reaches near 0 assuming that it has been paid off?

Thanks

If Peter hadn't missed the fourth payment than you would have been correct to assume that the balance of the loan reaches 0 at the end of 8-month period. However, as he misses the fourth payment, the amount of interest he pays over the duration of the loan increases. Therefore he does not fully pay off the loan at the end of the 8-month period as he initially predicted.

Imagine 7% interest on $500 and 7% interest on $400. The interest on the sum of $500 is greater. This is what happens in this scenario. As he doesn't reduce the principal of the loan for a month, the interest accrued is greater than what it normally should be and therefore he doesn't fully repay the loan within the period he had initially planned. Thus the answer is A and not C.

If you need any further clarification please let me know.

[Billion]

If Peter hadn't missed the fourth payment than you would have been correct to assume that the balance of the loan reaches 0 at the end of 8-month period. However, as he misses the fourth payment, the amount of interest he pays over the duration of the loan increases. Therefore he does not fully pay off the loan at the end of the 8-month period as he initially predicted.

Imagine 7% interest on $500 and 7% interest on $400. The interest on the sum of $500 is greater. This is what happens in this scenario. As he doesn't reduce the principal of the loan for a month, the interest accrued is greater than what it normally should be and therefore he doesn't fully repay the loan within the period he had initially planned. Thus the answer is A and not C.

If you need any further clarification please let me know.

Got it, makes sense.
Thanks

[Billion]

What is the question asking us to do?
I'm finding the shortest distance (the pole will be perpendicular to the wall) at which it will hit when it falls.
By doing this I obtain answer E, however the answer is C.
So I think I may be misinterpreting the question.

Thanks in advance.

;also question 3 from the VCAA 2010 exam 1 (MC)
I've never seen a question stated like that before, how exactly do we calculate the standard deviation?

[keltingmeith]

What is the question asking us to do?
I'm finding the shortest distance (the pole will be perpendicular to the wall) at which it will hit when it falls.
By doing this I obtain answer E, however the answer is C.
So I think I may be misinterpreting the question.

Thanks in advance.

;also question 3 from the VCAA 2010 exam 1 (MC)
I've never seen a question stated like that before, how exactly do we calculate the standard deviation?

This one's a doosy - if you don't quite get what I'm saying, tell me and I'll re-explain with pictures.

You're right in that the maximum height will be then the poll falls the shortest distance. When we know the shortest this distance, we can use this to find the height via pythag.

So, the first thing you need to do is find this distance. The way I did this was to use the cosine-rule to find either angle made by the wall and the lines leading to the pole. With that, I used sin(x)=O/H to find the perpendicular distance between the pole and the wall. After that, I used c^2=a^2+b^2 to find the height, so in numbers:

Solve(5^2=6^2+4^2-2*4*6*cos(x),x), x=0.9734 (I will call this x for ease)
sin(x)=O/4 ---> 4*sin(x)=3.307 (hence O)
4^2-O^2=5.0625
sqrt(5.0625) = 2.25, closest answer is 2.3 (C)

For your standard deviation one, simply take approximate percentages from the mean and add them up. The mean (from the box-and-whisker plot) is 180. So, I add the two bars either side together, and get 40. I add the next two, and get 68. From this, I would assume that one standard deviation from the mean is 2 degrees. To confirm, I keep doing this until I hit 95% (or close to it, since guestimating the y-axis). If I hit 95% after another 2 degrees, then using the 68-95-99.7% rule, I would say that the standard deviation is 2 degrees.

[Zealous]

What is the question asking us to do?
I'm finding the shortest distance (the pole will be perpendicular to the wall) at which it will hit when it falls.
By doing this I obtain answer E, however the answer is C.
So I think I may be misinterpreting the question.

First we need to find the red distance such that AT and MN are perpendicular which is the distance AT on the diagram.

We can do that if we can find out angle NMT first, then use angle NMT to find AT. Use the cos rule:



Now using angle NMT we want to find AT:



Now have a look at the blue triangle which is vertical (not on the floor), we can imagine the hypotenuse of this triangle to be the pole dropping, and we want ATP to form a triangle for the pole to fall and touch the wall. We'd get a triangle with hypotenuse 4m and on shorter end of 4.8379.

We can use pythagoras to find the height from A to P if P is lying on the wall.



Hence the answer is C.

Beaten by EulerFan! Just note that Euler's calculator is in radians - so don't freak out at x=0.9734.

[LiquidPaperz]

i think someone wanted question 8 of 2013 exam 1, so here it is

https://drive.google.com/folderview?id=0B4jDYm8MQMIFMFIxa2ZDdWhrY0U&usp=drive_web

[LiquidPaperz]

can someone tell me their answer for d (ii). i got 83% however answer has 17%. If i do area of the insignia/top its 17% but it asks for whats not covered so 100-17 = 83%

A of insignia 16.6, which is needed in the calc

[LiquidPaperz]

and technically speaking, shouldnt the answer is c be raised to the second power (the transition matrix)

answer has raised to 1

[LiquidPaperz]

struggling with this question

[myanacondadont]

struggling with this question

Looks like a further question so I'll give it a shot. I'm sure there's a way to do this considering one side is exactly twice the length of the other but I decided to do it the long way.

My thought process:
1.Find length AC using cosine rule
2. Use sine rule to find angle BAC
3. Since angle A is the same in both ABC and ABE we can then use it to deduce angle ABE (angle B)

1.  So using cos rule:

2.  Using sine rule:

                               

3. Due to triangle ABE being right angled we can say:

might not be right - I was expecting an integer due to the integer lengths of AB and BC. Did it another way and got Not sure if I have a rounding error somewhere but I'm confused now

[dyskontent]

struggling with this question

Let Angle ABE =



Solve for
=52.656