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AQA Mathematics MD01 Decision 1 – Friday 24th June [Exam Discussion Thread]

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I was feeling confident about this exam but after the other AQA exams I've had... (M1, C3) I'm really nervous about this one :/
My teacher thinks it's gonna be a tough one and they're gonna throw some algebra in there (like the nearest neighbour questions that have come up before) but he's not sure where.
Any predictions?
I'm expecting a lot of tough graph theory questions ('cause AQA hate us this year)

Which paper had algebra in? I don't remember doing a paper like that recently

And yeah AQA always hate us, not just this year :P

Reply 21

melrosepetal

Any advice on the 4 sorting algorithms??

Reply 22

yelash

Can anyone explain why the best lower bound for the travelling salesman problem is the highest option? I kind of get why the best upper bound is the lowest, but I don't get the lower bound rule.

Reply 23

Uzair142

Original post by shmelissas

Any advice on the 4 sorting algorithms??

Find the most illogical response and you'll get full marks

Reply 24

hi-zen-berg

Original post by yelash

Can anyone explain why the best lower bound for the travelling salesman problem is the highest option? I kind of get why the best upper bound is the lowest, but I don't get the lower bound rule.

I think basically, there is no foolproof method or algorithm to find a solution to a travelling salesman problem.

We use two algorithms, nearest neighbour (UB) and lower bound to find a range of values that the solution, X, may lie in.

As we want this range to be as small as possible ( Lower bound < X < Upper bound)

The best lower bound is the highest LB. best UB is lowest UB

Reply 25

LaurenLovesMaths

I find D1 the worse... even worse than D2...

IT'S NOT MATHS WHY DOES IT EXIST

Reply 26

User204395

After the horror that was C3 and C4 this'll be make or break for me and probably a lot of others.

Reply 27

kingowl

Original post by yelash

Which paper had algebra in? I don't remember doing a paper like that recently

And yeah AQA always hate us, not just this year :P

Ah, we got set some questions which I assumed were from past papers but doesn't look like they are. Not sure where it's from, maybe another exam board, but this is a couple things which my teacher thinks might might come up (or something similar)

Spoiler

(edited 7 years ago)

Reply 28

LaurenLovesMaths

Original post by User204395

After the horror that was C3 and C4 this'll be make or break for me and probably a lot of others.

It's got to be better than C3...

Reply 29

lucyjane_x

When they ask you to draw the minimum spanning tree for the lower bound in the travelling salesperson problem, and they ask you what can you conclude from the graph, what are the general things you have to say? Is there anything in particular you need to look for? I never seem to get those questions

Reply 30

username2635567

Often they expect you to pick up that the mst doesn't necessarily represent a tour (ie you can't go round all the edges and end up back where you started). Although the total weight of the mst is a lower bound for a minimum length tour, the tour it represents might not actually exist. This is also why the best lower bound is the highest lower bound (because it's more likely to actually exist). Hope this helped! 😊

Reply 31

Hjyu1

Original post by lucyjane_x

If your lower bound forms a Hamiltonian cycle it exists but if it doesn't then it's not a tour so doesn't exist

Reply 32

yelash

Original post by kingowl

Spoiler

Thx- I think something like that is fairly likely to be set, although i don't think the algebra will get any more complicated than this.

Reply 33

Eisobdxhsonw

Anyone actually know graph theory? I understand the basics of it but think they'll throw in some horrible ones I can't do, banking on the fact these papers usually take me an hour so I'll have half an hour to think about graph theory lol, those algebraic answers are from AQA past papers and the concepts are just the same, just involving algebra, nothing to worry about in fact it's probs better

Reply 34

lucyjane_x

Original post by Eisobdxhsonw

I am useless with graph theory lol but I understand everything else

Reply 35

yelash

Original post by lucyjane_x

I am useless with graph theory lol but I understand everything else

Yeah same XD. My score basically depends on the amount of graph theory. My score= (75-marks available for graph theory question)

Reply 36

yelash

Original post by kingowl

Could you post the answers to those questions as well plz?

Reply 37

Eisobdxhsonw

Original post by lucyjane_x

I am useless with graph theory lol but I understand everything else

Hoping that If no one can do graph theory, the more of it there is the lower the 100ums mark will be haha, always seem to make a few silly mistakes here and there and end up scraping 90 ums, literally would rather do stats

Reply 38

lucyjane_x

also when you have an objective line such as -x + 2y for example, how do you draw this on the graph because you can't draw it on the negative axis as they never include it, so how do you make it positive?