x Turn on thread page Beta
 You are Here: Home >< Maths

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

1. How long does it take to completely learn linear programming?
2. For a list of 7 numbers, the maximum number of comparisons in a bubble sort would be 6+5+4+3+2+1, which is an arithmetic series. Sn = 0.5 x 6(1 + 6) i.e. 0.5 n (first + last)
3. (Original post by tiny hobbit)
For a list of 7 numbers, the maximum number of comparisons in a bubble sort would be 6+5+4+3+2+1, which is an arithmetic series. Sn = 0.5 x 6(1 + 6) i.e. 0.5 n (first + last)
I completely forgot what an Arithmetic Series was. Okay thanks again Tiny Hobbit, I will get a C2/C1 Book from the Library after the Bank Holiday and try to make sense of this.

Just did January 2012....and well I think I may have scored above 70/75...My teacher will have around 6 of my Papers to Mark when we get back. I feel sorry for him.
4. (Original post by Skaterkid)
How long does it take to completely learn linear programming?
Learning it will take you a few hours, but Maths isn't about learning, you actually have to go through as many questions as possible. Especially in D1, where you don't get "Method Marks", you either do the Algorithm/Method Right or Wrong.

Go to Maths247 on Youtube for some quality videos. But again it's best to just read the book, then do as many questions as possible.
5. Can someone look at the d1 paper from may 2012, question 6b and tell me why node G finish event time is 25 and not 23

The red one is the correction from the mark scheme, which I think is wrong.
Can someone look at the d1 paper from may 2012, question 6b and tell me why node G finish event time is 25 and not 23

The red one is the correction from the mark scheme, which I think is wrong.

Posted from TSR Mobile
Attached Images

7. Thank, Sony worry about it, I realised my mistake, the dummy activity is going into j, not out of it.

Posted from TSR Mobile
8. No 25 is correct because when you work out the late time you have to look at the direction in which the line is going. With late time you have to look at the direction which is opposite
9. i hate d1, stupid pseudo-maths
10. (Original post by mkhat94:))
i hate d1, stupid pseudo-maths
Whilst it gets alot of criticism D1 has personally changed the way I think about all my subjects.

Take Physics for Example, I am no longer thinking in terms of "do I remember seeing a question like this in the past, or what little detail did I revise", and I am now thinking in terms of - what is the general solution to all questions relating to Electric and Magnetic Field, what is the Key Principle that governs this. i.e. what is the algorithm for attacking this problem.

Or in Chemistry, I am no longer thinking in terms of "details", but making that the second most important thing. My Priority now is always a Generalized approach to solving problems.

If I hadn't taken D1 I wouldn't have thought to change the way I have been revising in all my subjects. I personally think it is the best Unit I have taken in School, ever since dropping Humanities.

Whilst some may call it "easy" I think it is an essential part of the Curriculum and they should teach it in Year 7-9. Now I've done D1 for the last 2-3 Months, I can see myself getting A/A*s and meeting my Predicted Grades. Before - questionable.

It is easy but it is truly a great subject. Rant Over.
11. (Original post by Better)
Whilst it gets alot of criticism D1 has personally changed the way I think about all my subjects.

Take Physics for Example, I am no longer thinking in terms of "do I remember seeing a question like this in the past, or what little detail did I revise", and I am now thinking in terms of - what is the general solution to all questions relating to Electric and Magnetic Field, what is the Key Principle that governs this. i.e. what is the algorithm for attacking this problem.

Or in Chemistry, I am no longer thinking in terms of "details", but making that the second most important thing. My Priority now is always a Generalized approach to solving problems.

If I hadn't taken D1 I wouldn't have thought to change the way I have been revising in all my subjects. I personally think it is the best Unit I have taken in School, ever since dropping Humanities.

Whilst some may call it "easy" I think it is an essential part of the Curriculum and they should teach it in Year 7-9. Now I've done D1 for the last 2-3 Months, I can see myself getting A/A*s and meeting my Predicted Grades. Before - questionable.

It is easy but it is truly a great subject. Rant Over.
Nice post.
I like D1. It could be argued that its not as mathematically challenging as some units but its still intrinsically rewarding.

I have just finished all the D1 videos and managed to get scheduling up this weekend as that seemed to be the topic most people dislike!
12. (Original post by m4ths/maths247)
Nice post.
I like D1. It could be argued that its not as mathematically challenging as some units but its still intrinsically rewarding.

I have just finished all the D1 videos and managed to get scheduling up this weekend as that seemed to be the topic most people dislike!
Ah yes perfect thank you Sir!

Great timing as well, my Teacher says my Scheduling Diagrams never match with the Markscheme, I will check it out before I do my last 2 D1 Papers today!!

13. (Original post by Better)
Ah yes perfect thank you Sir!

Great timing as well, my Teacher says my Scheduling Diagrams never match with the Markscheme, I will check it out before I do my last 2 D1 Papers today!!

The solutions don't have to be unique which may be why.
14. (Original post by m4ths/maths247)
The solutions don't have to be unique which may be why.

For this part from one of your videos, I don't understand the need for a dummy at the start ?

15. (Original post by posthumus)

For this part from one of your videos, I don't understand the need for a dummy at the start ?

Activity A and B cannot start and end at the same event therefore a dummy is introduced to give them a unique route between the two events.

Its one of the two reasons a dummy is used. The other is multiple dependency.

Good luck in the exam
16. (Original post by m4ths/maths247)
Activity A and B cannot start and end at the same event therefore a dummy is introduced to give them a unique route between the two events.

Its one of the two reasons a dummy is used. The other is multiple dependency.

Good luck in the exam
Hi Maths247, what do you predict the topics that could potentially crop up next week?
17. (Original post by otrivine)
Hi Maths247, what do you predict the topics that could potentially crop up next week?
No idea!
I want to say something to make pupils think but have a feeling it will be the same questions as before but with different numbers!
Perhaps I'm being cynical
18. (Original post by m4ths/maths247)
Activity A and B cannot start and end at the same event therefore a dummy is introduced to give them a unique route between the two events.

Its one of the two reasons a dummy is used. The other is multiple dependency.

Good luck in the exam
So wait I can never do that sort of loop thing, no matter what ?
19. (Original post by m4ths/maths247)
No idea!
I want to say something to make pupils think but have a feeling it will be the same questions as before but with different numbers!
Perhaps I'm being cynical

I think bubble sort or quick sort,
i think drawing like the prescdence table ,

I am worried that they could ask scheduling but from your excellent tutorials, I no longer need to worry
20. (Original post by posthumus)
So wait I can never do that sort of loop thing, no matter what ?
Correct, no matter what.

By Definition each Activity must be shown Uniquely hence you cannot have a "loop" of Two Activities leaving the same Event (Node) and Ending at the same Event (Node).

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

### Four things top students are doing

Over the Easter break

### Her parents made her dump me

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

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