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Edexcel A2 D2 Mathematics June 2016 - Official Thread

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Original post by fpmaniac
Sorry for all the rookie questions, but how did they find the empty arc without going through augmenting process. In the book they have augmented one route then another route and then carried on until the Vertices after the first one all have saturated arcs.


in order to find a maximum flow, sometimes you have to reduce some flow routes in order to maximise another.

i dont know what you mean by how did they find the empty arc
Guys, I have a question. For dynamic programming, is it possible to get a maximin or minimax Question that's based on table(s) and not a diagraph / network ???????? or are tables only for maximum and minimum questions?
(edited 7 years ago)
Original post by NotNotBatman
Actually I think I understand it now. You're changing the direction of the flow, so that every arc in the route following A would have an extra 2 added to the flow.


Yup that's it!!
Original post by yesyesyesno
Guys, I have a question. For dynamic programming, is it possible to get a maximin or minimax Question that's based on table(s) and not a diagraph / network ???????? or is tables only for maximum and minimum questions?


You can get maximin/ minimax in worded problems too! Trying to learn it now
Original post by TrueDAN
You can get maximin/ minimax in worded problems too! Trying to learn it now


How can I?

There's never been a maximin/minimax problem for a table question, according to all of the past questions by topic anyways.
How would minimax and maximin for table and worded questions work? :s-smilie:
(edited 7 years ago)
Original post by yesyesyesno
How can I?

There's never been a maximin/minimax problem for a table question, according to all of the past questions by topic anyways.
How would minimax and maximin for table and worded questions work? :s-smilie:


Just found it now! Page 225 on the textbook.
(edited 7 years ago)
Original post by TrueDAN
No you can't I think sorry!!! Haha


are you are sure?
this is actually confusing me
Definitions?
Original post by KloppOClock
in order to find a maximum flow, sometimes you have to reduce some flow routes in order to maximise another.

i dont know what you mean by how did they find the empty arc


Dont worry I just got confused...I realised what I did wrong
Is it in anyway possible a game theory simplex question could come up?
Does anyone recommend drawing a diagram for DP through tables because I dont understand it no matter how much I try
Reply 111
Avatar for mxixbl
mxixbl
1
Original post by ReeceFraser
Is it in anyway possible a game theory simplex question could come up?


I'm also very curious about this, anyone got ideas?
Original post by fpmaniac
Does anyone recommend drawing a diagram for DP through tables because I dont understand it no matter how much I try


whats your problem with it
Original post by KloppOClock
whats your problem with it


First of all I cant even list the state stage action and destination...
Then its actually applying it to the problem
Original post by fpmaniac
First of all I cant even list the state stage action and destination...
Then its actually applying it to the problem


Same here, I mean how on earth am I supposed to know? and they are around 13 marks usually.
Sometimes they are generous though and give the first row of working and it can be worked out from there, I'm hoping we get that tomorrow.
Reply 115
Avatar for oinkk
oinkk
3
Original post by ReeceFraser
Is it in anyway possible a game theory simplex question could come up?


Original post by mxixbl
I'm also very curious about this, anyone got ideas?


It has only been tested once since 2002. Never on current-spec papers. It's a very rare question indeed.

But it is on the spec.

You will be guided through it. And there'll be simplex tableaux in the answer book. So you'll have no bother doing it.
Please can anyone explain question 17b here https://1cb7ab25ef4ef909bacd98c7d41ac3133a3bc3b6.googledrive.com/host/0B1ZiqBksUHNYN2pfX00xcDZuaGc/REV2.pdf I don't understand how one of the states for October can be 3 because in September none of the destinations are 3 so surely it wouldn't be possible to have 3 in stock at the start of October? Thanks :smile:
Can anyone help please? :smile:
(edited 7 years ago)
Original post by NotNotBatman
Same here, I mean how on earth am I supposed to know? and they are around 13 marks usually.
Sometimes they are generous though and give the first row of working and it can be worked out from there, I'm hoping we get that tomorrow.


Well you could try if you are really really stuck on it, drawing a diagram to illustrate. It will take longer but its better than nothing I guess. Thats my back up plan. Do you know any questions where they dont give you the first row?
Original post by fpmaniac
Well you could try if you are really really stuck on it, drawing a diagram to illustrate. It will take longer but its better than nothing I guess. Thats my back up plan. Do you know any questions where they dont give you the first row?


I've only done 3 papers, of those only June 2012 didn't have the first row, but they did give you the definitions of stage, state actions and destination in brackets.
It was the storage type; having done 2 examples of these, I think they are always the same.
How come in dynamic programming you have to start at the end and then work backwards? Why not work forwards? I know it's not a question that will come up but I have always wondered why and it was never explained to us.

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