D1 (Decision 1) 17 May 2013 Official Thread

I am confused at how you are supposed to format a trace table for a flow chart.

For example, in January D1 (2010), Q5(a)

http://www.edexcel.com/migrationdocuments/QP%20GCE%20Curriculum%202000/GCE%20January%202010%20-%20QP/6689_01_que_20100115.pdf


I filled the table out like this:



The mark scheme is filled out like this:



I looked at the text book and in the example in the book it puts each instruction (or box of instructions) on it's own new line. The mark scheme doesn't follow the format of the book's example so I'm not sure how to format it at all.

The mark-scheme seems to fill out the whole first row of the table until a new row is required, and then every new instruction after this goes on a new line. But I don't know if that's why it is set out like this.

Can anyone clarify how to fill out the table?

It is out for 5 marks and it looks like my answer would only get 1 mark. :l

I am doing the may 2008 paper and it has some odd questions... can someone tell me if there part of the specification or not...? Like this one....

..

Bro this is real last minute.... a lot of us haven't prepared for these types of questions as it came up in January this year. I would leave it if I were you and get some sleep... assuming your exam is in the morning good luck

Is there a way to remember which area you reject with equations like 2y>3x and such. I always forget how...

Forgot to post the pic, part d) makes no sense to me...


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Forgot to post the pic, part d) makes no sense to me...


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I am going to fail so badly tomorrow.

This afternoon/evening is the only time I've had to revise for it, and the stats exam is tomorrow morning as well. There's so much I don't know. I can't decide whether to accept that I will fail and get some sleep now, or try and learn it within the next couple of hours.

I am going to fail so badly tomorrow.

This afternoon/evening is the only time I've had to revise for it, and the stats exam is tomorrow morning as well. There's so much I don't know. I can't decide whether to accept that I will fail and get some sleep now, or try and learn it within the next couple of hours.

If I were you, I would forget about sleeping, and go revise now


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Dummy variable? I don't recognise that phrase. Are you referring to a "dummy" arc when doing critical path analysis? In which case it is used to show precedence where it would not be possible otherwise. Eg if tasks X and Y both rely on A, however task Y also relies on B. A would connect into X and B would connect into Y, and then a dummy would come out of the end of A to the beginning of Y.




Look at your chart, and see what activities absolutely have to go through that time. You may be able to move around some activities within their float to get them out of the way. Conversely you may be asked what activites can be happening at a certain time, in which case you move them about in their float in order to pass through.

You can find a lower bound for workers by looking at a Gantt chart be seeing what the maximum number of activities are that ever have to be going on at one time. If that many activties need to be done at once, you need at least that many workers.


I use an objective line to find the maximum profit. Say you have P = 3x + 5 y. Change that to y = (3/5)x+C/5 and draw the objective line on your graph. You should clearly be able to see the vertex of your region with the maximum profit by imagining the line shifting up the graph (or down the graph if you wanna minimise your objective). Fin the coords of the intersection by simultaneous equations and smack those numbers into P.

Think about it midday is theoretically the middle of the day. Lets say you had a gantt chart the time of day when you reach that day is midnight. and midday is the middle then midnight again so it's in the middle of the day. Draw a line directly down and whichever one it cuts into has to be happening. Now check to see if you can clear it all the way e.g. move it to the late time and if it still cuts then it must be happening,

That isn't a mistake, so you found the optimal value to be 24.7 using the point (120/17, 60/17) so then for an integer value, the closest points are (6,3) or (6,4), the one which maximises is (6,4)


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You test each point as an integer to find the correct solution so you put them back into the equations and see if it still is within the constraints. So basically for part b the x and y values should have been some fraction non whole number and you basically test the rounded up version and rounded down version of those numbers.

Anyways good luck guys hope it's a nice exam tomorrow unlike M1 .

Hey m4ths, didn't know you had a tsr account. Just wanted to say thanks for posting your videos, they've been a great help for pretty much all my A2 maths and further maths keep it up.