x Turn on thread page Beta
 You are Here: Home >< Maths

# Edexcel C3,C4 June 2013 Thread watch

1. C4 Solomon C question 4- part a (sorry can't seem to upload pictures)

Are supposed to cancel down the direction vector or does it matter if we don't? I've never seen an Edexcel one where we cancel down the direction vector so will it ever come up?
2. (Original post by Mallika)
C4 Solomon C question 4- part a (sorry can't seem to upload pictures)

Are supposed to cancel down the direction vector or does it matter if we don't? I've never seen an Edexcel one where we cancel down the direction vector so will it ever come up?
It doesn't matter if you don't,It just changes the value of lambda you get, but you will still end up with the right answer.
3. (Original post by brittanna)
It doesn't matter if you don't,It just changes the value of lambda you get, but you will still end up with the right answer.
That's what I thought but one of my answers for working out co-ordinates was really wrong It was probably just me!

Thank you!
4. (Original post by Mallika)
C4 Solomon C question 4- part a (sorry can't seem to upload pictures)

Are supposed to cancel down the direction vector or does it matter if we don't? I've never seen an Edexcel one where we cancel down the direction vector so will it ever come up?
I always simplify my direction vectors to the smallest whole numbers, because for one its make it easier to work with and 2 the markscheme usually right it with it there. As for your values for lambda it wont make a difference at all, when you need to find a certain point on the vector for example you will achieve a different lambda but it will be the right one when considering whether you simplified your direction vector or not. Basically it makes no difference.
5. Hey guys for iteration (c3) do we have to show working or can we go straight to what x1 is etc. from the calculator?
6. (Original post by sarah.102)
Hey guys for iteration (c3) do we have to show working or can we go straight to what x1 is etc. from the calculator?
you gotta show how to sub in the first value like x1 but the next 2 or 3 you can just right the answers
7. finally understanding c4 papers

just need to stop making silly mistakes, and crack down on those 2-3 hard questions in each paper
8. (Original post by cooldudeman)
I got the negative solutions by doibg cast anticlockwise...
I thought you are supposed to since the range has negative part?

Posted from TSR Mobile
i did cosinverse(3/4) and then put that angle in the negative quadrants in the CAST diagram, where the angle was 41.409... which is the same as cosinverse(-3/4) and putting that in the correct place in the CAST diagram.
so the angle 41.409 should be in the 2nd and 3rd quadrants and u shud get ..
x + 45 = 180 -41.409... ->x = 93.6
x + 45 = 180 + 41.409 .... -> = 176.4
x + 45 =/= -180 + 41.409 since its not in the range.

range was -180 < x<180 ----> -135<x+45<225
9. (Original post by internet001)
i did cosinverse(3/4) and then put that angle in the negative quadrants in the CAST diagram, where the angle was 41.409... which is the same as cosinverse(-3/4) and putting that in the correct place in the CAST diagram.
so the angle 41.409 should be in the 2nd and 3rd quadrants and u shud get ..
x + 45 = 180 -41.409... ->x = 93.6
x + 45 = 180 + 41.409 .... -> = 176.4
x + 45 =/= -180 + 41.409 since its not in the range.

range was -180 < x<180 ----> -135<x+45<225
Yeah I realised I did something retarded

Posted from TSR Mobile
10. (Original post by yaboy)
you gotta show how to sub in the first value like x1 but the next 2 or 3 you can just right the answers
Also just another quick question do you have to put units? e.g. I was asked to find the rate in a context and hence did so but didn't put units (apply it to the context) does that matter or would I lose a mark despite the maths being correct?
11. (Original post by sarah.102)
Also just another quick question do you have to put units? e.g. I was asked to find the rate in a context and hence did so but didn't put units (apply it to the context) does that matter or would I lose a mark despite the maths being correct?
usually not unless they say state the value in meter or cm or whatever is in then you have to.
12. how do you draw something to the power of x ? for example 5^x ?
13. (Original post by OG-Ashley)
how do you draw something to the power of x ? for example 5^x ?
Asymtope at y=0

Its meant to say 1 instead of 'a' btw. On the y line

Posted from TSR Mobile
Attached Images

14. in the formula booklet of c3

how can e^xlna become a^x?
can someone show me the steps?

thanks a lot!
15. (Original post by Lamalam)
in the formula booklet of c3

how can e^xlna become a^x?
can someone show me the steps?

thanks a lot!
As log laws from C2 apply for ln as well,

e^xlna= e^lna^x

Then the e and ln cancel to get..

a^x.

Hope that makes sense!
16. C1 and C2 are assumed knowledge for this paper and I was wondering if there is any C1/C2 formulae that everyone is revising? It would be my luck if I got stuck on a question because I couldn't remember the old formulae! Thanks
17. (Original post by ChelseaSam)
Anyone able to help me with Part B. I understand that the domain of f^-1(x) is equal to the range of f(x). The mark scheme says the domain is <= 4 however... the range for f(x) cannot equal 4 as x=/=1 and if you were to set your x value as say... -1.5 then your 4-ln(x) would be > 4. Am I mistaken or is the mark scheme incorrect? Thanks in advance
Anyone got any idea?? EDIT: x=/= -1 *
Attached Images

18. Im hoping for one hard and one easy/normal paper for c3 c4 a paper like c3 june 12 would be so ideal easy 100 ums im startin to get annoyed at one thing obviously you should be prepared as much as possible but it really can be a lottery sometimes when your aiming for 95+ there could be a dificult 2-4 marks in one paper or tricky 2-4 marks thts easy to slip olup on but on another paper its virtually a walk in the park its not fair why exams differ in dificulty why not just make all of the exams difficult these questions on a levels are repetitive this doesnt apply to most ppl on here but for those c-a students its even more of a lottery a easy ppr could mean difference between a or c :/ this applies to all maths papersquite an annoying feat some people will be lucky andvget an easy ride to an a or 90+ grade boundaries dont change much at all aswell i know how theyvwork but i still think its dodgy
19. Sorry bout my spelling i cant type on my phone i cant correct it as it takes too long to click the part i want to redo
20. (Original post by Revisionbug)
Im hoping for one hard and one easy/normal paper for c3 c4 a paper like c3 june 12 would be so ideal easy 100 ums im startin to get annoyed at one thing obviously you should be prepared as much as possible but it really can be a lottery sometimes when your aiming for 95+ there could be a dificult 2-4 marks in one paper or tricky 2-4 marks thts easy to slip olup on but on another paper its virtually a walk in the park its not fair why exams differ in dificulty why not just make all of the exams difficult these questions on a levels are repetitive this doesnt apply to most ppl on here but for those c-a students its even more of a lottery a easy ppr could mean difference between a or c :/ this applies to all maths papersquite an annoying feat some people will be lucky andvget an easy ride to an a or 90+ grade boundaries dont change much at all aswell i know how theyvwork but i still think its dodgy
The reason they put these trick questions in is to test you have 100% knowledge of the exam. Why should you not be able to answer all of the questions and still get an A? This separates the top grade students from the rest

Posted from TSR Mobile

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: September 24, 2013
Today on TSR

### Can you do this at Oxford?

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