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Edexcel A2 C4 Mathematics June 2015 - Official Thread

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Reply 1500

joe1545

Wouldn't mind a really nasty differential equation question, but a really nice vectors question.

Reply 1501

persononinternet

Original post by joe1545

Wouldn't mind a really nasty differential equation question, but a really nice vectors question.

ditto

Reply 1502

imnoteinstein

Original post by FKA Stiglitz

When you have your binomial expansion in the form

(1+ax)^n, it's valid for mod x < 1/a; for example a=2 so 2x, it's valid for mod x < 1/2.

thanks bruh

Reply 1503

Alice Moody

Anyone else dreading this exam tomorrow? im feeling confident!! but i did for C3 then opened the paper haha

Reply 1504

manlikem

Guys how do you know which value to make u for substitution? I get confused.. or can you just use any of the two vlues e.g sin x cos^3 x
I would have made cos^3 x to (cosx)^3 and then cosx= u but on the mark scheme they make sin x = u.
Why?

Reply 1505

humayra.ac

How do you this is it a standard pattern type ? thank

Screenshot 2015-06-15 17.47.46.png112.7KB

Reply 1506

sneha2096

Original post by Phenylethanone

how do you know when to use the normal formula for volume of revolution OR the one whens it a parametric curve?

usually u know it when they say it was turned 2pi or something like that most times they say the word revolution in the question

Reply 1507

raypalmer

Kmttt keep makin these likkle errors like forgetting to put the minus sign and i drop a lot of marks

Posted from TSR Mobile

Reply 1508

frozo123

https://5a302d29ff432793ce79475dd3dba997851918fc.googledrive.com/host/0B1ZiqBksUHNYNElsMEE2MDU0eWM/12%20Gold%202%20-%20C4%20Edexcel.pdf
how do you do question 2?

Reply 1509

Egg1

When doing integration by substitution, you know you have E.g. X=2u & you then find dx/du=2, from this point on do you have a way of knowing whether of not you:

flip that to get dx/du=1/2 and then just write at the end of your integral: 1/2du as then the two du's cancel, or from dx/du=2 should multiply both sides by du to get dx=2du ?

Hope that made sense

I've always done it the first way but Im not sure if im right

Reply 1510

MaySouth17

Original post by humayra.ac

How do you this is it a standard pattern type ? thank

Yeah but i got stuck on this and asked my teacher and she said its not in the edexcel syllabus anymore so don't worry about it

Reply 1511

Alice Moody

Original post by manlikem

I thought if you were to use substitution, it gave you the substitute? :smile:

Reply 1512

humayra.ac

oh really thanks :smile:

Original post by katie*may

Yeah but i got stuck on this and asked my teacher and she said its not in the edexcel syllabus anymore so don't worry about it

Reply 1513

humayra.ac

apply the a^x rule where if you differentiate a^X you get a^xlna

Original post by frozo123

https://5a302d29ff432793ce79475dd3dba997851918fc.googledrive.com/host/0B1ZiqBksUHNYNElsMEE2MDU0eWM/12%20Gold%202%20-%20C4%20Edexcel.pdf
how do you do question 2?

Reply 1514

manlikem

Original post by Alice Moody

I thought if you were to use substitution, it gave you the substitute? :smile:

what do you mean? The question is just integrate sinx cos^3 x dx

Reply 1515

frozo123

Original post by humayra.ac

apply the a^x rule where if you differentiate a^X you get a^xlna

that's what I was thinking but what you do with the 16? may you go through it :frown:

Reply 1516

Jamborambowambo

Does anyone know when you put the modulus bars wrapped around a function in- is it just when you integrate? And whether or not you can lose marks for putting in brackets instead?