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Edexcel FP2 Official 2016 Exam Thread - 8th June 2016

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What is the significance of this "dimple" proof in FP2? Haven't really seen it anywhere else and nothing listed in the spec.

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Reply 921

username1162972

Original post by paradoxequation

What is the significance of this "dimple" proof in FP2? Haven't really seen it anywhere else and nothing listed in the spec.

So you understand some of the maths going on and not blindly accept all the facts given.

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Reply 922

somevirtualguy

Original post by physicsmaths

So you understand some of the maths going on and not blindly accept all the facts given.

Posted from TSR Mobile

Could we be asked to prove it?

Reply 923

math42

Original post by somevirtualguy

Could we be asked to prove it?

Possibly if I recall correctly
It pretty much proves itself once you remember the initial reasoning about tangents though so just make sure you understand that
Though it's very unlikely to come up and if it did would probably give a bit of guidance

Reply 924

paradoxequation

Do we need to know the proofs for multiplying and dividing complex numbers? Thanks.

Reply 925

josephinemar25

Original post by jtt1998

Hi, does anybody have a link to the January 2016 IAL paper and mark scheme??
Sorry if this has already been posted, I can't find it anywhere!

I asked my teacher and she said that there wasn't IAL paper last January.

Reply 926

oinkk

Original post by paradoxequation

What is the significance of this "dimple" proof in FP2? Haven't really seen it anywhere else and nothing listed in the spec.

I think it's purely there to help you understand two things:

Use of finding tangents parallel & perpendicular to the initial line (stuff you're expected to know)

Sketching polar curves (you may get a mark for clearly showing the dimple or cardiod shape of your sketch).

Reply 927

coolguy123456

How do i do part a of this question? The MS is here but I don't understand why or how they did what they did.

https://8dedc505ac3fba908c50836f59059ccce5cd0f1e.googledrive.com/host/0B1ZiqBksUHNYdHIxUkJmdndfMlE/June%202006%20MS%20-%20FP2%20Edexcel.pdf

Reply 928

Kvothe the Arcane

Can someone show me step by step how they'd differentiate dy/dz wrt x?

Reply 929

Tizzydag

[QUOTE="coolguy123456;65489151"] Screen Shot 2016-06-06 at 09.55.24.png

Reply 930

somevirtualguy

Original post by coolguy123456

So 120/(2-t) is the coefficient of S, and as dS/dt is on its own we can say the Integrating Factor is the integral of 120/(2-t)... Then approach as you would

Reply 931

Jackmleitch

What is this form??? It's from the spec

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Reply 932

coolguy123456

Original post by somevirtualguy

So 120/(2-t) is the coefficient of S, and as dS/dt is on its own we can say the Integrating Factor is the integral of 120/(2-t)... Then approach as you would

Thank you both, I didn't realise we had to use an integrating factor, understood straight away once i read the words "integrating factor" 😂

(edited 7 years ago)

Reply 933

somevirtualguy

Original post by Kvothe the arcane

Can someone show me step by step how they'd differentiate dy/dz wrt x?

d/dx(dy/dz) = d^2y/dz^2 * dz/dx
As an overall we want to end up with it being with respect to x, so the dzs effectively cancel.

if we were to differentiate again

d^3y/dz^3 * (dz/dx)^2 + d^2y/dz^2 * d^2z/dx^2

Please correct me if wrong I always struggle to visualise it on my phone

(edited 7 years ago)

Reply 934

Jackmleitch

Original post by Jackmleitch

What is this form??? It's from the spec

Just realised its just:
2cosx = z + 1/z
2isinx = z - 1/z

Reply 935

justalawyer1998

For nth roots of a complex equation. does the value of theta used for k = 0, 1, 2, etc. always have to be between pi and -pi?

Reply 936

Tizzydag

Original post by Nikhilm

For nth roots of a complex equation. does the value of theta used for k = 0, 1, 2, etc. always have to be between pi and -pi?

it needs to be between the boundaries stated at the start. either pi -> -pi or 0->2pi

Reply 937

justalawyer1998

Original post by Tizzydag

it needs to be between the boundaries stated at the start. either pi -> -pi or 0->2pi

Normally there are no boundaries, so I assume that since it's an argument it's assumed pi to -pi?

Reply 938

Ayman!

Original post by Kvothe the arcane

Can someone show me step by step how they'd differentiate dy/dz wrt x?

$\frac{\mathrm{d} }{\mathrm{d} x}\left ( \frac{\mathrm{d} y}{\mathrm{d} z} \right ) = \frac{\mathrm{d} }{\mathrm{d} z}\left ( \frac{\mathrm{d} y}{\mathrm{d} z} \right ) \frac{\mathrm{d} z}{\mathrm{d} x} = \frac{\mathrm{d} z}{\mathrm{d} x}\frac{\mathrm{d}^{2} y}{\mathrm{d} z^{2}}$

Think of it as if the dz's cancel each other out in the second line. :smile:

(edited 7 years ago)

Reply 939

Kvothe the Arcane

Thanks @Ayman!.

I guess I see it now (though not directly).

I guess I'll use a temporary sub to make it easier to see. I asked because it was in 2014(R) Q 8.