This discussion is now closed.

Check out other Related discussions

D1 edexcel jan 05

mik1w

you cant use a back flow if it makes the flow negative, you can only take from a edge that already has a flow going the right way. otherwise you would be going against the direction of the edge.

for the example I said a network of pipes, each pipe has a water filter that only works in one direction. sneaky huh? :biggrin:

correct me if i am wrong, but isnt that the whole point of back flow (going against direction). however i guess it is 40 seeing as its me against everyone in the world, lol

btw gaz backflow i got SCBFT - 1 and SCEDT - 3 and u forgot SCDT -2
then i cut BF, CF, CE, CD AD of flow 42 on mine

soz havent got a scanner mate.

Reply 21

MdSalih

Adil Bhai

correct me if i am wrong, but isnt that the whole point of back flow (going against direction). however i guess it is 40 seeing as its me against everyone in the world, lol

btw gaz backflow i got SCBFT - 1 and SCEDT - 3 and u forgot SCDT -2
then i cut BF, CF, CE, CD AD of flow 42 on mine

soz havent got a scanner mate.

Could you type up the question.. and describe the network as best possible.

Just this question is really bugging me :frown:

MdSalih

Reply 22

RobbieC

15

I think I got 40 or 42... but I could NOT FIND A MIN CUT FOR IT!!!

I didnt draw the network, as that was RANDOM and I cant draw them... So I lost 5 marks for sure... I couldnt find the cut but stated the name of the theorem, so lost 2 there.

I am sure I screwed up simplex even though I am traditionally good with it.

I am so utterly devastated... after 20 minutes I had decided I was retaking it. Besides the first question on that paper, the WHOLE format was disasterously random, and bore little similarity to any of 5 past papers I have done, all of which I have achieved B- to A on...

I will be lucky to get a C/D in that trainwreck paper today... I didnt have time to finsih....

Answer spaces were missing, so i had to write things next to graphs in mid air, and it was just so poorly formatted. Im very disappointed... I just hate when boards randomly alter the format of exams... Even those slight changes can throw people off...

:frown:

how depressing...

Reply 23

MdSalih

RobbieC

I just hate when boards randomly alter the format of exams... Even those slight changes can throw people off...

As annoying as it may be... the stucture/layout of the paper shouldn't really matter.. as its examining your knowledge.. I understand it has the potential to throw you off, but shouldn't really be dependant on the paper format as much.

The questions themselves were in the same structure as past paper Q's.. although they have been playing with the answer booklet format for D1 since they started it... dont think the Jan '05 ones were that different to the Jun '04 though.

MdSalih

Reply 24

Adil Bhai

Robbie dont worry about it mate, concentrate on the other exams.

btw could u tell me how to get feedback from cam, my teachers said they will get it, but it still hasnt come

Reply 25

Gaz031

15

Adil Bhai

correct me if i am wrong, but isnt that the whole point of back flow (going against direction). however i guess it is 40 seeing as its me against everyone in the world, lol

btw gaz backflow i got SCBFT - 1 and SCEDT - 3 and u forgot SCDT -2
then i cut BF, CF, CE, CD AD of flow 42 on mine

soz havent got a scanner mate.

CD is already saturated. It has a capacity and flow of 2 on my diagram.

Reply 26

john !!

OP

14

Adil Bhai

correct me if i am wrong, but isnt that the whole point of back flow (going against direction).

no, the edges were directed which means you can only have a flow in the direction of the arrow. a backflow is once you already have a flow in the correct direction through the pipe, and reduce the flow. you can't have a backflow through a pipe which has flow 0 in the first place because that would leave you with a negative flow.

Reply 27

RobbieC

15

Adil Bhai

Robbie dont worry about it mate, concentrate on the other exams.

btw could u tell me how to get feedback from cam, my teachers said they will get it, but it still hasnt come

You need to send off and ask for it through your referee, I believe... At least to get the proper feedback you do.

I think the format does matter, and that simplex question was RANDOM. If they had not drawn any of the tableau and just let me do the WHOLE simplex alogrithm myslef for 15 marks or something, that would have been so much better. They gave me NO room to explain my operations... and while that probably only pushed me toward a lower U than I already had, or D/E whatever, its still slightly annoying.

Id rather have not had an AB but blank pages instead, and im not even kidding, cos thats how ive done all past papers before and I did fine then!

D1 edexcel jan 05

Related discussions

Latest

Trending

Trending

Articles for you