You are Here: Home >< Maths

# Edexcel D1 Jan 23 2013 Revision thread watch

Announcements
1. (Original post by WavingFLag)
We discussed this earlier and concluded that the way you lay out table doesn't matter as long as output is correct. Judging by how many lines you get you can work out when to move on to next line. Usually move onto next line when you go back to beginning of flow chart. But it honestly doesn't matter, don't worry about it.
Thank you very much!!!
+rep

Edit: Also thanks for the useful tips!
2. I thought flow charts were not in the sylabus anymore?
3. (Original post by WavingFLag)
Tips
1) When scheduling make sure you consider a) the lowest late event time in deciding which activity to do next and b) that the activity follows the activity before it. Eg don't put down d before c if d comes after c in activity network
2) When ordering for binary seach use quick sort rather than bubble
3) When trying to work out why you can't get complete matching look for 2 people who can only do the same job e.g a and b can only do activity 3. Or look for someone who does 2 jobs no one else can do, so that if they do one there is no one to do other e.g b can do 3 & 4 and no one else can do either.
4) When calculating late/early event time, remember early time has to be as high as it can be and late time has to be as low. Don't overlook dummies.

Final tip? Go to bed, for D1 you need to be sharp and well rested otherwise you'll make mistakes. Good luck all

By the way anyone know how to plot objective line? I do it by swapping x and y co-efficients. Any help would be appreciated.
If the scale of the axis is good, then I just swap the x and y co-efficients but if not I just find the a common denominator of the coefficients that will give me good co-ordinates for the graph scale i.e. 5x + 2y = 10 and then work out the y and x values when both are 0 i.e. 0 + 2y = 10 so y = 5 (0,5), when y = 0 5x + 0 = 10 so x = 2 (2,0)

Good luck everyone for the exam!
4. If we use kruskals do we have to say "reject all other arcs" once finished?
5. Good luck everyone!
6. (Original post by FLLF)
If we use kruskals do we have to say "reject all other arcs" once finished?
I would yes! Just say reject all or list them eg reject ab, reject dg etc
7. unofficial markscheme any1?
8. (Original post by samfreak)
unofficial markscheme any1?
http://www.thestudentroom.co.uk/show...8#post41192028
9. Hi arsey thank you for the mark scheme

For question 1 i got NO,NO,yes did we had to state the values next to it, cause it said is so i thought either Yes or no would be fine? second question on route inspection the 11600£ i did multiply 9 arcs x 80 will that get 1 mark? in route insepction the 6 marks how much is method mark you can get? Lastly, for the route in dijakstra did we have to state 29? i gave the route
10. Messed up heavily on question 1 and linear problem, never dealt with either of them before. Definitely got a B but don't think I got enough to get an A
11. What a coincidence that a trace table came up...
I personally found that to be the most annoying question in the exam.

When it asked what happens if E was -8 I had no idea so just wrote it would give the negative square root of 72...hope that's right

What did everyone write for the number of iterations for question 2?
12. (Original post by Kishan91)
What a coincidence that a trace table came up...
I personally found that to be the most annoying question in the exam.

When it asked what happens if E was -8 I had no idea so just wrote it would give the negative square root of 72...hope that's right

What did everyone write for the number of iterations for question 2?
should be right for the -8. The question said it gave the square root and it gives the negative answer so the negative the square root is the same surely.....

iterations i put 4 but no one seems to know if once you have one it counts as an iteration to look at it
13. (Original post by mattd75)
should be right for the -8. The question said it gave the square root and it gives the negative answer so the negative the square root is the same surely.....

iterations i put 4 but no one seems to know if once you have one it counts as an iteration to look at it
i put in 5 iterations
14. it will be interesting to see what they make the answer or if they just give both answers the mark
15. (Original post by Dr. I Was Here)
i put in 5 iterations
5 iterations is correct,
But mathematically you need to use logarithms to find that.

There are 26 letters in alphabet.
Every time you halve the list in binary search until you get your single letter.

Therefore 26 * (1/2)^n = 1

Then take logarithms of both sides and so on...
16. (Original post by otrivine)
Hi arsey thank you for the mark scheme

For question 1 i got NO,NO,yes did we had to state the values next to it, cause it said is so i thought either Yes or no would be fine? second question on route inspection the 11600£ i did multiply 9 arcs x 80 will that get 1 mark? in route insepction the 6 marks how much is method mark you can get? Lastly, for the route in dijakstra did we have to state 29? i gave the route
i think i got 11600 aswell so you will get you Answer mark for that
17. Grade Boundaries are out today.
(80 UMS) A - 62
(70 UMS) B - 56
(60 UMS) C - 50
(50 UMS) D - 44
(40 UMS) E - 39

Those are actually a really nice set of Grade Boundaries for D1, and the lowest they've ever been for a January Exam!
Good Luck to everyone for tomorrow
18. Re-sat and went from 64 to 82. Quite pleased.
19. Well, getting a B was a bit of a WTF moment. I know I lost 1 mark, but I thought I got the rest! Time to get mah paper back. For curiosity's sake.

D1 is such an odd module.
20. (Original post by BaconFTW)
Well, getting a B was a bit of a WTF moment. I know I lost 1 mark, but I thought I got the rest! Time to get mah paper back. For curiosity's sake.

D1 is such an odd module.
Same are you retaking too? The results at my school were a lot lower this year, about 10-20% lower than usual! One person got a U and was predicted an A/B!

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: May 17, 2013
Today on TSR

And I hate it

### University open days

• Manchester Metropolitan University
Wed, 14 Nov '18
• University of Chester
Wed, 14 Nov '18
• Anglia Ruskin University
Ambitious, driven, developing your career & employability? Aspiring in your field, up-skilling after a career break? Then our Postgrad Open Evening is for you. Postgraduate
Wed, 14 Nov '18
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