Edexcel FP2 Official 2016 Exam Thread - 8th June 2016

https://8fd9eafbb84fdb32c73d8e44d980d7008581d86e.googledrive.com/host/0B1ZiqBksUHNYTnpyeF8xQlZweHc/CH3.pdf

Someone explain Page 61 part c, how did they come to the conclusion of working out the points and radius pls

Reply 222

Original post by Mihael_Keehl

@Zacken

Hi for (z+1)^3 = -1,

the roots of z do not equal 0 can you expalin why pls, is it because there is a constant attached to z?

What do you mean? Are you saying that one of the roots should be z=0?

That's obviously not possible since (0+1)^3 = 1^3 =/= -1

Reply 223

Original post by Zacken

What do you mean? Are you saying that one of the roots should be z=0?

That's obviously not possible since (0+1)^3 = 1^3 =/= -1

no lmfao, I did not mean that, that is obvious haha.

I mean the sum of the roots of unity do not equal zero, as what is the case for other types where z is isolated in FP2 Chapter 3 Ex3E.

Reply 224

Original post by Mihael_Keehl

no lmfao, I did not mean that, that is obvious haha.

I mean the sum of the roots of unity do not equal zero, as what is the case for other types where z is isolated in FP2 Chapter 3 Ex3E.

Because these aren't the roots of unity - they're the roots of -1. The roots of unity are the roots of 1...

Reply 225

Original post by Zacken

Because these aren't the roots of unity - they're the roots of -1. The roots of unity are the roots of 1...

don't most of the roots in fp2 dmt types have the roots add up to zero, I have obeserved this serveral times..

Reply 226

Original post by Mihael_Keehl

don't most of the roots in fp2 dmt types have the roots add up to zero, I have obeserved this serveral times..

They probably add to -3 in this case. Because

( z_1+1) + (z_2+1)+(z_3+1)=0

Reply 227

Original post by EricPiphany

They probably add to -3 in this case. Because

( z_1+1) + (z_2+1)+(z_3+1)=0

I think it is just -2. :smile:

Reply 228

Original post by Mihael_Keehl

I think it is just -2. :smile:

That's weird. What did I do wrong?

Reply 229

Original post by Mihael_Keehl

I think it is just -2. :smile:

It's -3. I just checked it.

Reply 230

Original post by EricPiphany

It's -3. I just checked it.

Original post by Mihael_Keehl

I think it is just -2. :smile:

I agree with Eric, the solutionbank lists the wrong answer down at the end.

Reply 231

economicss

Please could someone explain for the method of differences how you know what cancels when there's 3 parts to the partial fraction, like in question 20b here https://8fd9eafbb84fdb32c73d8e44d980d7008581d86e.googledrive.com/host/0B1ZiqBksUHNYTnpyeF8xQlZweHc/REV1.pdf I can see it's obvious when the question has 2 terms but I can't figure it out when there's 3? :smile:

Thanks

Reply 232

Original post by EricPiphany

It's -3. I just checked it.

the roots are -2, -1/2 + isqrt3 /2 and 1/2 - isqrt3 /2 according to the document.

However I get a different answer, I was reading off the previous document before Lol.

Reply 233

Original post by economicss

Thanks

when you write enough of the columns at most when you have 5 rows, you will observe a pattern and then you cancel accordingly.

Reply 234

From ex 7b 5b

can we express 4/(1+sin2x) in terms of cosecx?

Why can it not be written as 4 (1+ cosec2x)

Reply 235

Page 7 part c

I put 3/sqrt2 [cosec (45 - theta)] is that acceptable?

Reply 236

Original post by Mihael_Keehl

From ex 7b 5b

can we express 4/(1+sin2x) in terms of cosecx?

Why can it not be written as 4 (1+ cosec2x)

\frac{1}{1+\sin 2x} \neq 1 + \frac{1}{\sin 2x} = 1 + \csc 2x

Reply 237

Original post by Zacken

\frac{1}{1+\sin 2x} \neq 1 + \frac{1}{\sin 2x} = 1 + \csc 2x

I see, thnk you

Reply 238

economicss

Hi, please could someone explain how you find the area in question 63 of rev 2 https://8fd9eafbb84fdb32c73d8e44d980d7008581d86e.googledrive.com/host/0B1ZiqBksUHNYTnpyeF8xQlZweHc/REV2.pdf, is there a general method to follow when finding areas of overlapping regions? Thanks :smile:

Reply 239