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Oxford MAT 2013/2014

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instead of a minus you can simply take the absolute value of the integral from k to 2 (which will always be positive, as the area has to e positive)
that's what we did in my Math HL class... Still could be wrong but in the end gives out the same result

I think putting a minus in these is much simpler than getting absolute value functions involved, which really aren't necessary in this case since it's clear that the second integral is always negative.

Reply 1141

Tarquin Digby

Original post by dutchmaths

But wasn't that the point? They never said that the area had to be positive. Also, I'm fairly sure I forgot one part of this question, would you mind filling me in? Something about f_k-2(x)=-f_k(x)

There is no such thing as negative area, so if they said give a function for the area between 0 and 2, you would have to consider the positive and negative areas separately, since integration doesn't give you area, it gives you signed area, which is quite different. If they were just interested in the signed area, then they obviously wouldn't have asked you to express it using 2 different integrals.

I'm a Cam applicant so didn't do the MAT, so unfortunately I can't help with the filling in.

Reply 1142

dutchmaths

Original post by Tarquin Digby

Well, this just makes me sad. This is probably a language problem and likely something I would have caught if the test were in Dutch. I think I did fairly well on the rest of the question though. (I hope)

Reply 1143

Tarquin Digby

Original post by dutchmaths

While I'm at it, here's a sketch of question 2. Again, I'm hoping people will reply to this comment and expand on it/correct me.

Q2:
(i) For k=/=±1, we have a function f(x) that satisfies:
f(x)-k*f(1-x)=x
Find f(x) by replacing x with 1-x

I was absolutely clueless on this one. The answer I ended up giving was k=0 and f(x)=x, which technically is correct, but probably not what they were looking for.

(ii) We redefine the function f(x) as follows:
f(x)-f(1-x)=g(x)
Show that there is no solution for f(x) if g(x)=x

I solved this by replacing x with 1-x, and proving some paradoxical property of x. I think it was x=-(1-x)=x-1. I don't quite remember, though, and my answer might not have been correct.

(iii) What condition does g(x) have to satisfy for there to be a valid f(x)?

The answer I ended up giving was: g(x) has to be a polynomial with components of an even degree. I figured this was the only way this weird type of symmetry would crop up. Again, I probably had this wrong.

(iv) What is f(x) if g(x)=(2x+1)³?

I had no idea. Also, the g(x) I give here is probably incorrect, but it was something similar to this.

For part (i):

f(x) - kf(1-x) = x

Substitute

x = 1-x

to get

f(1-x) - kf(x) = 1 - x

Multiply both sides by

k

to get

kf(1-x) - k^2f(x) = k(1-x)

Add this to the first equation to get

(1-k^2)f(x) = k(1-x) + x[br]\implies f(x)=\dfrac{k(1-x)+x}{1-k^2}

Reply 1144

kapur

Original post by dutchmaths

for the 3rd part, i got g(x) + g(1-x)=0

also for q4, how did you transform the graph of fk(X) to that of F2-k(X)?

Reply 1145

jadoreétudier

Original post by dutchmaths

What did people get on the first question? I was fairly sure is was a>2 but now I'm not sure anymore.
Could we set up a document of all multiple choice questions and the answers that everybody agrees on? I'm sure our collective memory is good enough to remember all the questions!

I had a>2 aswell. But I'm not so sure anymore either and I can't remember the exact question.
I'm confident I have 2 answers correct in multichoice - sinx+4 and 28. What is life?

Reply 1146

seohyun

Original post by jadoreétudier

I had a>2 aswell. But I'm not so sure anymore either and I can't remember the exact question.
I'm confident I have 2 answers correct in multichoice - sinx+4 and 28. What is life?

I discussed it with a friend and she was right, I chose a>2 while she chose a/=2. :frown:

Sent from my GT-N7100 using Tapatalk 4

Reply 1147

jadoreétudier

Original post by seohyun

I discussed it with a friend and she was right, I chose a>2 while she chose a/=2. :frown:

Sent from my GT-N7100 using Tapatalk 4

Think I better change my vote in the poll from 61-70 to 51-60. Ha.

Reply 1148

OxfordMathsDept

Original post by President Snow

Yes, usually slightly higher. They also assured someone else here a couple of years ago that they definitely do not compare scores across different applied for degrees, not that anybody necessarily expected them to.

Just to clear this up -- as you all will have seen when you took the paper on Wednesday, Maths and Computer Science, Computer Science, and Computer Science and Philosophy applicants do different questions to Maths, Maths and Stats, and Maths and Philosophy applicants.

As such, the marks aren't directly comparable and the threshold is chosen separately. There's no systematic reason that one of the thresholds should be higher. Hope that helps!

Reply 1149

kapur

Original post by OxfordMathsDept

will the answers to the paper be published on the website soon?

Reply 1150

Titus20

Original post by OxfordMathsDept

Hi, do you have any idea when we'll be told if we're wanted for interview or not?

Reply 1151

Noble.

Original post by Titus20

Hi, do you have any idea when we'll be told if we're wanted for interview or not?

If the last five years are anything to go by, end of November to the first week of December.

Reply 1152

Titus20

Original post by Noble.

If the last five years are anything to go by, end of November to the first week of December.

Thank you.

Reply 1153

Noble.

Original post by kapur

will the answers to the paper be published on the website soon?

If by soon you mean the next 4-12 months, then yes :tongue:

When I was applying I'm pretty sure the solutions didn't appear until way after all decision were made (it might not have been until the start of the academic year of entry actually).

Reply 1154

Arcane1729

Original post by OxfordMathsDept

Can I ask who marks the scripts please-
and i also have a query- if you have the correct working out for a multiple choice question but pick the wrong answer will your effort be recognised?
One question said- for what values of 'a' are there distinct roots?
got
(a-2)^2 > 0

and deduced that is so for all a forgeting it said distinct so when a=2 it becomes 0 so answer is a/=2.

Will I really be punished for this so heavily- or will my working get credit- its so unfair that little slips but general good understanding can be punished heavily by losing a good 4 marks.

Reply 1155

Blazy

Original post by President Snow

Also, according to my maths teacher, when providing feedback after the process is over, for the first year ever, they will NOT be releasing our MAT scores. Apparently every other admissions test (ELAT, PAT, CAT, BMAT, TSA, etc.) will still provide raw marks, but we will never get our marks back. :frown:

Anyone else heard this or have a reliable source?

Somebody correct me if I'm wrong but I thought you never get your MAT score back unless you ask the college you interviewed at directly. Some colleges have a policy of not giving successful applicants their marks back as well.

(edited 10 years ago)

Reply 1156

Arcane1729

Original post by Blazy

I think it is because there may psychological effect on the undergraduate when they start uni courses- if they got low- they may think they are the worst of the bunch that got in and feel intimidated by other students- and obviously the converse for those who do well :smile:

- something like that I suspect anyway

Reply 1157

JosephML

Original post by nahomyemane778

Given that they ask you to put rough working between each part for the multiple choice would suggest that they do look at your rough working, however, it also says that marks are only given for correct answers so you will lose 4 marks for this question.