You are Here: Home >< Maths

# D1 (Decision 1) 17 May 2013 Official Thread watch

1. (Original post by Better)
Can anyone help me on Question 3 part C

"State with a reason, which of the two vertices should be chosen to minimise the length of the new route".

The mark scheme isn't very clear at all. I thought if you did this you are essentially eliminating 2/4 nodes, hence you want to pick the 2 Odd Nodes with the Path between them of lowest weight.

In the markscheme they pick the path of heighest weight.

Practice Paper A.pdf (222.5 KB, 644 views)

D1 practice paper A mark scheme.doc
You specifically start and end at the two odd nodes that have the longest path between them so that you only need to repeat the shortest path between the other two odd vertices and hence, the length of the new route is minimised.
2. (Original post by Epic Flawless)
You specifically start and end at the two odd nodes that have the longest path between them so that you only need to repeat the shortest path between the other two odd vertices and hence, the length of the new route is minimised.

Boom!!! Okay thank you, very glad you cleared that up. That's pretty much Route Inspection Cleared up for me then.

How would you say this in Exam Terms?

Something like - "To minimize the to Total Path, choose the Pair of Greatest Weight, (then you state the Odd Nodes) hence meaning you will be able to repeat the Shortest Route. This will have mean the new route is minimized? "
3. (Original post by study beats)
i think D1 is much much easier than C3 and C4, infact working through the book, i found it as easy as C1..

ur right, its not like core maths at all.....in fact u dont need much maths knowledge to do it anyway....
Yeah your right; but I really enjoy it, it clicks with my way of thinking more than any other subject has. And it is really helping me alot on Chemistry, and Physics. I'm finding myself trying to find generalized ways to solve problems now, so I am glad I chose D1 over S1.

It has really emphasized to me that to get to a solution you just have to do the same thing over and over again, and its mundane but you will get there.

I will be studying Comp Sci anyway, so I pretty much have to like this subject. So I am glad I do.
4. (Original post by Better)
Boom!!! Okay thank you, very glad you cleared that up. That's pretty much Route Inspection Cleared up for me then.

How would you say this in Exam Terms?o

Something like - "To minimize the to Total Path, choose the Pair of Greatest Weight, (then you state the Odd Nodes) hence meaning you will be able to repeat the Shortest Route. This will have mean the new route is minimized? "

(Original post by Epic Flawless)
You specifically start and end at the two odd nodes that have the longest path between them so that you only need to repeat the shortest path between the other two odd vertices and hence, the length of the new route is minimised.
That's not quite it.

Choose the pair of odd nodes that have the shortest route between them. Repeat that bit. The other 2 odd nodes will be the start and finish nodes, in either order. The route between these last 2 nodes may or may not be the longest possible repeat.
5. (Original post by tiny hobbit)
That's not quite it.

Choose the pair of odd nodes that have the shortest route between them. Repeat that bit. The other 2 odd nodes will be the start and finish nodes, in either order. The route between these last 2 nodes may or may not be the longest possible repeat.
Yeah this made much more sense, as the goal is the shortest route. I was confused, thank you for clearing that up.

The one you repeat, is always the shortest. And if it goes from 4-->2 Odd Nodes i.e. Non-Eulerian ---> Eulerian, the other Route weight will be irrelevant it just depends on the First Pair you chose.

Thank you, hopefully the Markschemes won't be odd when I start doing 2006-2012 papers.
6. (Original post by tiny hobbit)
That's not quite it.

Choose the pair of odd nodes that have the shortest route between them. Repeat that bit. The other 2 odd nodes will be the start and finish nodes, in either order. The route between these last 2 nodes may or may not be the longest possible repeat.
Also Tiny Hobbit how many past papers have you done?
7. (Original post by Better)
Yeah your right; but I really enjoy it, it clicks with my way of thinking more than any other subject has. And it is really helping me alot on Chemistry, and Physics. I'm finding myself trying to find generalized ways to solve problems now, so I am glad I chose D1 over S1.

It has really emphasized to me that to get to a solution you just have to do the same thing over and over again, and its mundane but you will get there.

I will be studying Comp Sci anyway, so I pretty much have to like this subject. So I am glad I do.
i am doing M3, FP2 and D1 lol
8. (Original post by study beats)
i am doing M3, FP2 and D1 lol
Ah good luck mate, I don't do Further Maths. But yeah Lets do this - we're all gonna make it brah!
9. (Original post by Better)
Ah good luck mate, I don't do Further Maths. But yeah Lets do this - we're all gonna make it brah!
i just finished D1 like yesterday, i havent done like any M3 or FP2 at all, i am seruously f*****
10. Is okay if I just the review exercises 1 and 2 in the edexcel d1 book?

By okay i mean to get 100ums.

The reason I'm asking is cos I might not have enough time to do all the exercises
11. Who else has problem with time in the exam ??? (If any of you are retaking)

I ended up with 50 UMS which brought my maths grade right down :/

Also I lost a lot of accuracy marks I feel like there isn't much I can do with this is exam !!!
I genuinely found it easier than all other maths modules I've done but I ended up with a pretty low mark.

Damn really regret taking it, I chose it because of Computer Science.... turns out S1 would have been more relevant !
12. (Original post by Vorsah)
Is okay if I just the review exercises 1 and 2 in the edexcel d1 book?

By okay i mean to get 100ums.

The reason I'm asking is cos I might not have enough time to do all the exercises
You will most likely understand all the concepts yes, but unless your a perfectionist you will need a lot of practice to get near 100 UMS.

Also I learnt that time is a major issue in this exam, therefore I recommend you time yourself with a couple of past papers before you sit the exam !
13. (Original post by posthumus)
Who else has problem with time in the exam ??? (If any of you are retaking)

I ended up with 50 UMS which brought my maths grade right down :/

Also I lost a lot of accuracy marks I feel like there isn't much I can do with this is exam !!!
I genuinely found it easier than all other maths modules I've done but I ended up with a pretty low mark.

Damn really regret taking it, I chose it because of Computer Science.... turns out S1 would have been more relevant !
I'm studying Comp Sci too.

Oxford University state the modules you do are irrelevant as long as you are A* caliber Maths student, but state D1 will give you the best feel of Comp Sci.

I'm doing Past Papers and making sure that I never make the same mistake twice, the people on this forum are great students and can answer questions too if the Book or your Teacher can't help you.
14. (Original post by posthumus)
You will most likely understand all the concepts yes, but unless your a perfectionist you will need a lot of practice to get near 100 UMS.

Also I learnt that time is a major issue in this exam, therefore I recommend you time yourself with a couple of past papers before you sit the exam !
Good recommendation, I'm about to do a Paper now timed in 1 hour, D1 Definitely seems about timing, and being very explicit with your working.

For me personally the Questions which take me around 10-15 mins are the Linear Programming and the Critical Path Analysis Questions, so trying to work hard to get to that golden 69+/75 Spot. (which is ironically only an A grade for D1).
15. (Original post by Better)
I'm studying Comp Sci too.

Oxford University state the modules you do are irrelevant as long as you are A* caliber Maths student, but state D1 will give you the best feel of Comp Sci.

I'm doing Past Papers and making sure that I never make the same mistake twice, the people on this forum are great students and can answer questions too if the Book or your Teacher can't help you.
Yh these module choices don't matter so much, but speaking to a lecturer at Cambridge he told me that they prefer S1 and that D1 can give people the wrong impression of what discrete mathematics is really like. D2 is a lot more relevant however I think Further Maths is the most useful for computer science (unfortunately I didn't take it )

I will keep doing past papers, thanks !

(they get pretty damn tedious after a while )
16. (Original post by posthumus)
Yh these module choices don't matter so much, but speaking to a lecturer at Cambridge he told me that they prefer S1 and that D1 can give people the wrong impression of what discrete mathematics is really like. D2 is a lot more relevant however I think Further Maths is the most useful for computer science (unfortunately I didn't take it )

I will keep doing past papers, thanks !

(they get pretty damn tedious after a while )
I didn't take FM too but literally when I went on a Uni open day they were like none of that stuff matters.

One guy was Top 10 in his year for Computer Science and he did Maths Economics and Politics. He got A*AA. He was just like I liked maths, and computer science seemed to be related, so I thought it will be good.

The University will pretty much teach you everything you need to know, just focus on the grades. One of the best Professors in the world for Comp Sci, told me I don't need to read any extra books either during the holidays, he said just focus on being getting top a-levels then mastering the Uni Syllabus as I go along. He said, that's how you succeed.

Just saying because I was like you a few months ago, but when it comes to Academia its not complex - make sure to be the best at it on the day of the exam! Don't worry too much about all that extra stuff, I'm sure you are a great student. Let's do this!

About to do a past paper D1 Practice Paper B: 1Hr30 mins wish me luck!!!
17. (Original post by Better)
Also Tiny Hobbit how many past papers have you done?
All of them from 2001 onwards - perhaps I should mention that I am a teacher and have been teaching it since then.

I find that reading comments on TSR helps me to understand the misconceptions that my own students have.

If you do any papers before 2009, remember that some topics moved from D1 to D2. Don't do any questions on flows in networks, Simplex or planarity.
18. (Original post by tiny hobbit)
All of them from 2001 onwards - perhaps I should mention that I am a teacher and have been teaching it since then.

I find that reading comments on TSR helps me to understand the misconceptions that my own students have.

If you do any papers before 2009, remember that some topics moved from D1 to D2. Don't do any questions on flows in networks, Simplex or planarity.
Ah I see! I think I should call you Mrs Tiny Hobbit then, or Mrs Hobbit to be polite... :/ Not sure that will work though

But Thank you very much then, for taking the time to come on here! I hope you can help us in our Journey's to A*s.

Do you have any recommendations based on students that you've taught. I.e. anythings they should focus on in the Exam.

I'm finding it difficult to Mark my own D1 Papers.
19. (Original post by Better)
I didn't take FM too but literally when I went on a Uni open day they were like none of that stuff matters.

One guy was Top 10 in his year for Computer Science and he did Maths Economics and Politics. He got A*AA. He was just like I liked maths, and computer science seemed to be related, so I thought it will be good.

The University will pretty much teach you everything you need to know, just focus on the grades. One of the best Professors in the world for Comp Sci, told me I don't need to read any extra books either during the holidays, he said just focus on being getting top a-levels then mastering the Uni Syllabus as I go along. He said, that's how you succeed.

Just saying because I was like you a few months ago, but when it comes to Academia its not complex - make sure to be the best at it on the day of the exam! Don't worry too much about all that extra stuff, I'm sure you are a great student. Let's do this!

About to do a past paper D1 Practice Paper B: 1Hr30 mins wish me luck!!!
Ah yes definitely ! I really meant that I took D1 with the wrong impression with respect to CS Can't wait till University

And good luck !

Posted from TSR Mobile
20. (Original post by Better)
Ah I see! I think I should call you Mrs Tiny Hobbit then, or Mrs Hobbit to be polite... :/ Not sure that will work though

But Thank you very much then, for taking the time to come on here! I hope you can help us in our Journey's to A*s.

Do you have any recommendations based on students that you've taught. I.e. anythings they should focus on in the Exam.

I'm finding it difficult to Mark my own D1 Papers.
At the college where I teach, the students call teachers by their first names, so Tiny Hobbit will be fine!

The main thing is to write down enough (probably more than you think that you should) to make your method clear. I feel sorry for those candidates who teach themselves D1 or have to mark their own D1 papers. It is the one module where you really need someone who knows what they are doing to mark your papers - and no, I am not volunteering, I hate marking D1. In fact, I must go and mark some D1 homework .

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: August 15, 2013
Today on TSR

### The most controversial member on TSR?

Who do you think it is...

### Is confrontation required?

Discussions on TSR

• Latest
Poll
Useful resources

Can you help? Study help unanswered threadsStudy Help rules and posting guidelinesLaTex guide for writing equations on TSR

## Groups associated with this forum:

View associated groups
Discussions on TSR

• Latest

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE