2014 Mathematical Methods Exam 2 Paper + Solutions (MCQ + ER)

[swagsxcboi]

if I didn't put units in the majority of my answers, will I loose one mark per answer

nah you'll be fine, you don't need units.

[NyaTaku]

For 2f. I used 10 instead of -10 and ended up with a positive answer. How many marks will I lose for that?

1 mark if they're mean, 2 if they're brutal.

nah you'll be fine, you don't need units.

Can't tell if serious

[swagsxcboi]

1 mark if they're mean, 2 if they're brutal.

Can't tell if serious

In methods, you NEVER are required to write units. Ever. There are no exceptions. Every question can be answered to full marks without writing units.

The only time you write units is if YOU have changed the units of the answer you are stating, in which case you have changed the magnitude of the answer and must justify it with the appropriate unit of measurement. Like the question "Find the height in cm of the plant to the nearest mm" or whatever it was, unless you converted your answer to mm, you can simply leave it unitless.

check previous assessment reports

[speedy]

check previous assessment reports

In Euler's stupid question thread, someone apparently emailed VCAA and they said to include them.

Edit: I am on the side of not including them though - however I did just in case :S

[swagsxcboi]

solutions for first 20 MC
apologies for messy working, just ask for clarification
didn't do the last two MC because I have no idea how to

[chuck981996]

Hey for question 4d i calculated the z value using .15 as area which gives  z=-1.03643.
I then calculated standerd devition using squareroot(intergral from 0 to 50 of (x-25)^2 * h(x) dx).
then i solved z=(x-25)/standard deviation just caluated for x.
i got 13.7227 for x, have i completely overcomplicated this and will get 0 marks?
cheers

The height isn't normally distributed, I'm afraid. It's governed by the PDF given on page 19. I'm sorry to say it but I don't think that answer can be awarded any marks.

if I didn't put units in the majority of my answers, will I loose one mark per answer

I think you may have been given misinformation by other people here, or confusing information, so I will tell you what I think:

If you don't have an SI unit like m or m^3 you will lose a mark. If you don't have a unit like "wombats" you will probably lose a mark - but it depends what other people did. I'm so sorry to tell you this.

Can someone explain why q2f is m/hr and not m/yr for units?

Ugh omfg because I'm stupid. You're right: it should be m/yr. Sorry about that.

Edit: updated it in the OP.

[jumcakes]

I think the units can depend slightly on the nature of the question - for example 1)c) I don't think requires units (n(10) = 1000, since n is the number of wombats).

On the other hand, 1)b) might need units (maximum is 1600 wombats, minimum 800 wombats, since the question is asking for the maximum populations rather than the range of n. I'm under the impression that if they asked for the maximum/minimum of n(t), 1600 and 800 without units would be acceptable.

Another example would be that it's fine to say the period is 6, instead of 6 hours, but again depends on the nature of the question.

[Aman476]

I know this should be in the spec from but given chuck is here haha, has anyone seen last years answer to exam 2 question 2 b they ask you to graph the locus points such that:

|z+congjug(z)| = |z-conjug(z)|

i ended up with x^2 = y^2 and so that y = sqrt(x^2) = |x|

but if you think about what it's saying  -  the distance between z and the negative of its conjugate being equal to distance between z and its conjugate being equal it is any point along y = x and y=-x (this is what vcaa say as well) my question is why this doesn't come out in the algebra?

[speedy]

I know this should be in the spec from but given chuck is here haha, has anyone seen last years answer to exam 2 question 2 b they ask you to graph the locus points such that:

|z+congjug(z)| = |z-conjug(z)|

i ended up with x^2 = y^2 and so that y = sqrt(x^2) = |x|

but if you think about what it's saying  -  the distance between z and the negative of its conjugate being equal to distance between z and its conjugate being equal it is any point along y = x and y=-x (this is what vcaa say as well) my question is why this doesn't come out in the algebra?

I don't understand this? y = |x| = +/- x

[Aman476]

I don't understand this? y = |x| = +/- x

|x| = +x
|-x| = x

you only get the parts of the lines above the x axis, but the answer is the lines unrestricted (so i drew like a modulus, but the answer is just two lines going on forever, -x and +x

[Conic]

x^2 = y^2 and so that y = sqrt(x^2) = |x|

It should be rather than , since you took the square root of both sides, and is the pair of lines and . You could also do this using another method:

[Aman476]

It should be rather than , since you took the square root of both sides, and is the pair of lines and . You could also do this using another method:

OMGGGG thankyouuuuuu haha

[Mayesy]

Can someone please explain why question 9 in mc is A and not E?

[simondaaanng]

Q4e. "Find the minimum value of n". Wouldn't it be n=14 instead of n>=14?

[NyaTaku]

Q4e. "Find the minimum value of n". Wouldn't it be n=14 instead of n>=14?

n=14, pretty sure it's been said already.