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D1 EDEXCEL -> 20th MAY 2011 EXAM THREAD+Paper & Solutions in 1st Post

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Reply 40

jones_wise

Original post by letsdothetimewarpagain

https://rapidshare.com/files/611017682/all_d1.zip

Just sent these to fudgezilla but should be useful for everyone =)

Thank you. :smile:

Reply 41

sickomann

Can anyone explain the matchings chapter, i missed that week in college and i just cant seem to understand it from the book :frown:

Reply 42

sohail.s

Original post by ilyking

why don't you just draw it, use your ruler and go across the page and the last vertex is the maximum? I'm pretty sure you don't have to check every corner

yeah i do that at the end but im just too used to vertex testing :P , so at the end i have just under half an hour to check and drawing a profit line is something i'd do to confirm my answer

Reply 43

ad2010

Original post by sickomann

Can anyone explain the matchings chapter, i missed that week in college and i just cant seem to understand it from the book :frown:

which parttt?

Reply 44

sickomann

Original post by ad2010

which parttt?

preferably the whole thing :frown:

i kinda get whats going on, but how do i get the first matching and the maximum mathing

Reply 45

ad2010

Original post by sickomann

preferably the whole thing :frown:

i kinda get whats going on, but how do i get the first matching and the maximum mathing

try out these notes :smile:

http://integralmaths.org/resources/file.php/19/D1_Edexcel_2008/2_Graphs/Section_2/EdExceld1g2n.pdf
if they don't make sense either then i'll explain :smile:

Reply 46

sickomann

Original post by ad2010

try out these notes :smile:

http://integralmaths.org/resources/file.php/19/D1_Edexcel_2008/2_Graphs/Section_2/EdExceld1g2n.pdf
if they don't make sense either then i'll explain :smile:

It needs me to be logged in D:

Reply 47

sickomann

Original post by ad2010

try out these notes :smile:

http://integralmaths.org/resources/file.php/19/D1_Edexcel_2008/2_Graphs/Section_2/EdExceld1g2n.pdf
if they don't make sense either then i'll explain :smile:

It requires a login D:

Reply 48

sickomann

it wont let me open the link without login details D;

Reply 49

ilyking

Original post by Willdearn

what so just write the first letter instead of the full names?
Yeah i think so it makes it so much easier

no, im talking about linking the letters:

so a=1, b=2, c=3..... z=26.

I can't order letters, but I can order numbers much more easily

Reply 50

sickomann

aha thanks :tongue:

ill give this a read and if it still makes as much sense as a noodle house, ill post :smile:

(quote feature isnt working so soz for the inconvenience)

Reply 51

ad2010

Original post by ilyking

no, im talking about linking the letters:

so a=1, b=2, c=3..... z=26.

I can't order letters, but I can order numbers much more easily

yeah that's what I was talking about, my teacher said not to do that because it takes up too much time and defeats the purpose of using the sort somehow, it's better to just use the first letter of what they give you, sort it that wayy.

Reply 52

ad2010

Original post by sickomann

aha thanks :tongue:

ill give this a read and if it still makes as much sense as a noodle house, ill post :smile:

(quote feature isnt working so soz for the inconvenience)

okayy

Reply 53

hyn_shayan

D1 isn't that hard. It's just about timing and making sure you don't miss up one of the questions because you could lose loads of marks. I'm sitting it alongside my GCSE's so it should be fine. Good luck!

Reply 54

tt123

both the ruler/objective line and vertex methods are specified in the syllabus therefore its risky only learning one, i prefer the vertex method myself, its more logical, also learn some crucial definitions as they have come up in the past. With linear programming, if the question is in context and you need to find optimal points, make sure you're points are integers because in the may 2009 paper the question did not specify but the mark scheme states that you have to for the last mark

Reply 55

Willdearn

Original post by ilyking

no, im talking about linking the letters:

so a=1, b=2, c=3..... z=26.

I can't order letters, but I can order numbers much more easily

haha oh I see what you mean

Reply 56

Willdearn

Original post by giraffegiraffe

i think you can do the branch thing and then just go along one of the branches til you hit breakthrough. then you dont need to carry on or still do the second branch. :smile:

oh ok thanks

Reply 57

Groat

Original post by giraffegiraffe

also - on linear programming graphs, on inequality lines does it matter if we shade the side of the line that we want, as long as we label the feasible region? (or does it have to be shading the side of the line that you dont want) - unless the Q says specifically?

Shade out to be sure.

Reply 58

tt123

Original post by giraffegiraffe

that is a good point- if it is something like selling cakes and you 'cant have 0.7 of a cake' then round to the next integer value which would still fit in the feasible region ... right?

there are two ways of doing it one is to select the last solution covered by the objective line as it leaves the feasible region(maximise) or as it enters the feasible region(minimise), I don't bother with objective lines unless the question specifically asks for it, the second method for those of you who prefer vertex testing is to test the integer solutions that are close to the optimal(non integer) solution, for example if your non integer solution is (4.5, 5.5), Test (4,5), (4,6) (5,5) and (5,6), (Also check that these integer solutions that are being tested lie in the feasible region, if they are not you do not need to test them) and the one with the lowest or highest(minimise or maximise, depending on what your asked) outcome when substituted into the equation is the optimal integer solution. Also method 1 will not work if the feasible region isn't sufficiently clear to identify integer solutions accurately.