Edexcel FP2 June 2015 - Official Thread Watch

username1259045
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#61
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#61
(Original post by Mjmuk)
What paper are you referring to?
questions paper: http://www.scribd.com/doc/31959719/F...Paper-A#scribd
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hotdigdy
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#62
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When they ask you to 'use de Moivre's theorem' to prove trigonometric identities, do we have to use (cos(x) +isin (x))^n or can we use (z+1/z)^n etc.?
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InOrbit
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#63
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#63
(Original post by hotdigdy)
When they ask you to 'use de Moivre's theorem' to prove trigonometric identities, do we have to use (cos(x) +isin (x))^n or can we use (z+1/z)^n etc.?
Use ((r(cos(x)+isin(x)))^n = r^ncos(nx)+isin(nx) to make multiple angle trig identies to power identities. Use z^n+1/z^n=2cos(nx) and z^n-1/z^n=2sin(nx) to make power trig identities into multiple angle ones.

Power identities are useful for solving equations; multiple angle identities are useful for integration.
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math42
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#64
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#64
(Original post by hotdigdy)
When they ask you to 'use de Moivre's theorem' to prove trigonometric identities, do we have to use (cos(x) +isin (x))^n or can we use (z+1/z)^n etc.?
You're supposed to learn the identities for z^n +/- 1/(z^n) so that should be fine
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TeeEm
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#65
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#65
http://www.thestudentroom.co.uk/show....php?t=3353445
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V0ldemort17
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#66
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#66
Guys, solution bank does this in Q12 last part Mixed exercise 3I:


u^2 + (4-v)^2 = 4

u^2 + (v-4)^2 = 4

Why does it go from -v to +v?
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crashMATHS
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#67
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#67
(Original post by V0ldemort17)
Guys, solution bank does this in Q12 last part Mixed exercise 3I:


u^2 + (4-v)^2 = 4

u^2 + (v-4)^2 = 4

Why does it go from -v to +v?
Expand it out. You get the same thing.

Think of it like this:

(4-v)^2 = [(-1)(v-4)]^2

= (v-4)^2


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InOrbit
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#68
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#68
(Original post by V0ldemort17)
Guys, solution bank does this in Q12 last part Mixed exercise 3I:


u^2 + (4-v)^2 = 4

u^2 + (v-4)^2 = 4

Why does it go from -v to +v?
Mod(1-v)

Take a factor of -1 out of the modulus sign:
Mod(-1)(Mod(-1+v)

Mod(-1) = 1, therefore:

Mod(1-v) = Mod(v-1)
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llIllIllIllI
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#69
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#69
9 days in, absolutely bricking myself now
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Abel Demoz
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#70
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#70
Who can explain the working out to part b?
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InOrbit
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#71
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#71
(Original post by Abel Demoz)
Who can explain the working out to part b?
Integrate between the intersections you have just worked out. Take one curve, minus the other and you're done. It's not intuitive at first, but once you've worked it out, you can see why it works. You essentially cut the curves at two half lines, so get rid of excess area.
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abeldemoz
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#72
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(Original post by Alex:)
Integrate between the intersections you have just worked out. Take one curve, minus the other and you're done. It's not intuitive at first, but once you've worked it out, you can see why it works. You essentially cut the curves at two half lines, so get rid of excess area.
Lol that's what I did but my answer was wrong because I made a sign error in my working out. I only noticed the error after I posted the question. My method was correct though. Sorry to waste your time.
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jf1994
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#73
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#73
Anyone got any resources for FP2? I've been going off of examsolutions and my understanding and ability to answer questions on loci, transformations and differential equations is still really sketchy...
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TeeEm
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#74
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#74
(Original post by jf1994)
Anyone got any resources for FP2? I've been going off of examsolutions and my understanding and ability to answer questions on loci, transformations and differential equations is still really sketchy...
more resources at
http://www.thestudentroom.co.uk/show....php?t=3353445
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bobabob
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#75
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guys I liked FP2 all the way through year 13, but now when it came to doing a lot of past papers I just find it so difficult - when I am doing a timed paper I am sweating, my head is exploding, I don't have enough time and just it is so so bad even though when paper is a standard one

Does anyone else have the same?
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username1259045
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#76
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#76
(Original post by bobabob)
guys I liked FP2 all the way through year 13, but now when it came to doing a lot of past papers I just find it so difficult - when I am doing a timed paper I am sweating, my head is exploding, I don't have enough time and just it is so so bad even though when paper is a standard one

Does anyone else have the same?
omg this is me! i liked fp2 throughout the whole year (self-studying) and i understood everything, I only did the questions in the book though, and then i started past papers and i at first i was like ???!! why am i finding this difficult?? but then i kept doing a lot, and now i got the hang of it the more you'll do the better you'll get! also for the complex numbers, the transformations can be a bit tricky but once you get the hang of it it's fine!

if you need any help, don't be afraid to ask! good luck, it'll get better trust me!
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Damien_Dalgaard
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#77
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#77
(Original post by mmms95)
omg this is me! i liked fp2 throughout the whole year (self-studying) and i understood everything, I only did the questions in the book though, and then i started past papers and i at first i was like ???!! why am i finding this difficult?? but then i kept doing a lot, and now i got the hang of it the more you'll do the better you'll get! also for the complex numbers, the transformations can be a bit tricky but once you get the hang of it it's fine!

if you need any help, don't be afraid to ask! good luck, it'll get better trust me!
Hi you know for 2nd order DE where b^2 - 4ac >0 does it matter which way m is, in the CF.

Thanks!
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username1259045
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#78
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(Original post by Damien_Dalgaard)
Hi you know for 2nd order DE where b^2 - 4ac >0 does it matter which way m is, in the CF.

Thanks!
sorry i don't quite follow... are you asking about the number of roots to know what the CF is or..? i don't use b^2-4ac though to get it
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math42
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#79
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#79
(Original post by Damien_Dalgaard)
Hi you know for 2nd order DE where b^2 - 4ac >0 does it matter which way m is, in the CF.

Thanks!
Do you mean if you have distinct roots m1 and m2 then does it matter in what order you put them in within the CF. i.e. y = Aem1x + Bem2x or y = Aem2x + Bem1x ? If so, no, as A and B are both arbitrary you are expressing the same general solution whichever order the different m roots are in
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Damien_Dalgaard
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#80
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#80
(Original post by mmms95)
sorry i don't quite follow... are you asking about the number of roots to know what the CF is or..? i don't use b^2-4ac though to get it
(Original post by 13 1 20 8 42)
Do you mean if you have distinct roots m1 and m2 then does it matter in what order you put them in within the CF. i.e. y = Aem1x + Bem2x or y = Aem2x + Bem1x ? If so, no, as A and B are both arbitrary you are expressing the same general solution whichever order the different m roots are in
Thank you both, the second response was what I meant to ask.Thank you guys I understand.
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