The Edexcel C3 (14/06/12 - AM) Revision Thread
Maths exam discussion - share revision tips in preparation for GCSE, A Level and other maths exams and discuss how they went afterwards.
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Re: The Edexcel C3 (14/06/12 - AM) Revision Threadcan you not do straight way saying lets consider the cotx=y then solve it with ys then get the anwers and convert the cot to 1/tan? and get values?(Original post by arvin_infinity)
convert all cot to 1/tan
then basically use double angle identity for tan2x
you should get a quadratic
then solve the quadratic
in this domain -π/2<x<π/2 my ans. are π/4 and -1.03
quote me if the method is still not clear -
Re: The Edexcel C3 (14/06/12 - AM) Revision Thread(Original post by ViralRiver)
x.
You know when we sketch functions ..are we supposed to sketch the f(x) and also sketch the function required!
It's actually more work if you include the actual function cuz say you transform the function e.g. f(2x) you need to stretch the func. and show how is different to the actual function.
please quote me on that -
Re: The Edexcel C3 (14/06/12 - AM) Revision Threadyh why not..but try it and see if you get the ans. above (let's hope my ans. are the right ans.)(Original post by otrivine)
can you not do straight way saying lets consider the cotx=y then solve it with ys then get the anwers and convert the cot to 1/tan? and get values?
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Re: The Edexcel C3 (14/06/12 - AM) Revision ThreadI AM getting in degrees 128,38??(Original post by arvin_infinity)
yh why not..but try it and see if you get the ans. above (let's hope my ans. are the right ans.)
did you get
1/4tanx=1?
then tanx=1/0.25
tanx=4
then find the degrees then +180
then divide by 2>? -
Re: The Edexcel C3 (14/06/12 - AM) Revision ThreadI didn't lose any marks for just showing the final result when I took the paper. If in doubt, or you think you'll make a mistake, start with f(x) and draw graphs for each consequent transformation.(Original post by arvin_infinity)
You know when we sketch functions ..are we supposed to sketch the f(x) and also sketch the function required!
It's actually more work if you include the actual function cuz say you transform the function e.g. f(2x) you need to stretch the func. and show how is different to the actual function.
please quote me on that -
Re: The Edexcel C3 (14/06/12 - AM) Revision ThreadYh I didn;t loose any mark neither ..so am gonna go with "ONLY showing the results"(Original post by ViralRiver)
I didn't lose any marks for just showing the final result when I took the paper. If in doubt, or you think you'll make a mistake, start with f(x) and draw graphs for each consequent transformation.
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Re: The Edexcel C3 (14/06/12 - AM) Revision ThreadI AM getting in degrees 128,38??(Original post by arvin_infinity)
Yh I didn;t loose any mark neither ..so am gonna go with "ONLY showing the results"
did you get
1/4tanx=1?
then tanx=1/0.25
tanx=4
then find the degrees then +180
then divide by 2? -
Re: The Edexcel C3 (14/06/12 - AM) Revision ThreadYou got it wrong..try again ..my ans. was like tanx=1 and tanx=-5/3(Original post by otrivine)
I AM getting in degrees 128,38??
did you get
1/4tanx=1?
then tanx=1/0.25
tanx=4
then find the degrees then +180
then divide by 2>?
EIDT:I think I got it wrong too..!!! am gonna do it again lolLast edited by arvin_infinity; 04-06-2012 at 12:54. -
Re: The Edexcel C3 (14/06/12 - AM) Revision Threaddid you get a 1/4(Original post by arvin_infinity)
You got it wrong..try again ..my ans. was like tanx=1 and tanx=-5/3
i did 3y+y=1
4y=1
y=1/4
right or wrong? -
Re: The Edexcel C3 (14/06/12 - AM) Revision Threadright so you cannot consider them as y can you please show me how you did? is this meant to be the harderst question(Original post by arvin_infinity)
checked mine again..it's right..only π/4 is not going to be a valid ans. just cuz tan(2* π/4 ) is not defined. -
Re: The Edexcel C3 (14/06/12 - AM) Revision Threadhaha sorry mate you have to memorise all those graphs they ask translations and stuff from there i remember doing one or two in a solomon paper(Original post by knowledgecorruptz)
Quick question guys: Chapter 6, we don't seriously have to memorise all those graphs, do we? -
Re: The Edexcel C3 (14/06/12 - AM) Revision ThreadOHMYGOD...it's now like they're particularly complex or anything but what the hell's the point!?(Original post by 99llewellyn99)
haha sorry mate you have to memorise all those graphs they ask translations and stuff from there i remember doing one or two in a solomon paper -
Re: The Edexcel C3 (14/06/12 - AM) Revision ThreadLike which graph? as in exponential and ln and etc ?(Original post by knowledgecorruptz)
Quick question guys: Chapter 6, we don't seriously have to memorise all those graphs, do we?
Dont have the textbook so not sure
you know you have to find R and convert it to the formula which you obtained perhaps in the previous parts of the same questions..if you post the value of R and the statement of R(cos ...) I should be able to tell you why(Original post by The Anomaly)
please help it will be really appriciated and i will +ve rep
thanks
and please quote me when you answer
thanks again
Doubt it..there are harder ..well it's just because comes up once ..makes it harder(Original post by otrivine)
right so you cannot consider them as y can you please show me how you did? is this meant to be the harderst question
post your working I should be able to say where you got wrong -
Re: The Edexcel C3 (14/06/12 - AM) Revision Threaddid you get a 1/4(Original post by arvin_infinity)
Like which graph? as in exponential and ln and etc ?
Dont have the textbook so not sure
you know you have to find R and convert it to the formula which you obtained perhaps in the previous parts of the same questions..if you post the value of R and the statement of R(cos ...) I should be able to tell you why
Doubt it..there are harder ..well it's just because comes up once ..makes it harder
post your working I should be able to say where you got wrong
i did 3y+y=1
4y=1
y=1/4
right or wrong? -
Re: The Edexcel C3 (14/06/12 - AM) Revision ThreadYou have to learn the general shape of the e^x, ln(x) graph as well as the shapes of the sin(x), cos(x), tan(x), sec(x), cosec(x) and cot(x) graph.(Original post by knowledgecorruptz)
Quick question guys: Chapter 6, we don't seriously have to memorise all those graphs, do we?
I did see a question which wanted you to draw what 2sec(2x) would look like.
You know that the graph would begin at y=2 because of the 2sec(2x) part
Then you know that the graph has to repeat twice at 0 < x < pi because of the 2sec(2x) part -
Re: The Edexcel C3 (14/06/12 - AM) Revision ThreadJust learnt them, they looked really intimidating at first so I got a little worried...they're pretty straightforward. Can I just ask, how general is "general"? I know the rough shape, I mean they're not looking for an accurate gradient of the curve, are they?(Original post by James A)
You have to learn the general shape of the e^x, ln(x) graph as well as the shapes of the sin(x), cos(x), tan(x), sec(x), cosec(x) and cot(x) graph.
I did see a question which wanted you to draw what 2sec(2x) would look like.
You know that the graph would begin at y=2 because of the 2sec(2x) part
Then you know that the graph has to repeat twice at 0 < x < pi because of the 2sec(2x) part
And if you draw a dodgy curve (like I did in C1, haha), you'd still get the marks as long as the vague shape's there, and you've got all the important points labelled, right? The co-ordinates are the main bit.