Year 12s: what will be the first way you research your future options? >>

Edexcel A2 C4 Mathematics June 2016 - Official Thread

Scroll to see replies

Reply 2280

Snasher350

Original post by joodaa

do we need to know how to integrate/differentiate arccosx arcsinx and arctanx?

Not for C4 no. FP3 yes

Reply 2281

Craig1998

Original post by Supermanxxxxxx

ImageUploadedByStudent Room1464898372.643066.jpg

I just don't understand what's happened on step 2 of 8b

Posted from TSR Mobile

If you ever are stuck with an integral, consider substitutions like u = x+1 for this question, it may not be clear to see the 1-1, and it may be a little longer, but it'll give you the answer.

\pi\int_0^3 \frac{x}{x+1} dx[br]u = x+1[br]du/dx = 1 leads to dx = du[br]Limits changed to 1 and 4[br][br]=\pi\int_1^4 \frac{x}{u} du[br]=\pi\int_1^4 \frac{u-1}{u} du[br]=\pi\int_1^4 1 - \frac{1}{u} du[br]=\pi[u - ln|u|]_1^4[br]=\pi(4 - ln4 - 1 + ln1)[br]=\pi(3-ln4)

(edited 7 years ago)

Reply 2282

joodaa

Original post by Snasher350

Not for C4 no. FP3 yes

Ah okay thanks I came across a madas question with it and had noo idea what to do few

Reply 2283

thad33

Sorry guys already asked but the madas exam papers, are all those questions what feature in the individual topic questions or are they different questions?

Posted from TSR Mobile

Reply 2284

Supermanxxxxxx

Original post by Craig1998

If you ever are stuck with an integral, consider substitutions like u = x+1 for this question, it may not be clear to see the 1-1, and it may be a little longer, but it'll give you the answer.

\pi\int_0^3 \frac{x}{x+1} dx[br]u = x+1[br]du/dx = 1 leads to dx = du[br]Limits changed to 1 and 4[br][br]=\pi\int_1^4 \frac{x}{u} du[br]=\pi\int_1^4 \frac{u-1}{u} du[br]=\pi\int_1^4 1 - \frac{1}{u} du[br]=\pi[u - ln|u|]_1^4[br]=\pi(4 - ln4 - 1 + ln1)[br]=\pi(3-ln4)

Cheers brah I was thinking of doing that but didn't believe it would work

Posted from TSR Mobile

Reply 2285

Supermanxxxxxx

And anyone have any tips on vectors even after exam solutions I am so confused.

Posted from TSR Mobile

Reply 2286

Ayman!

Original post by Supermanxxxxxx

And anyone have any tips on vectors even after exam solutions I am so confused.

Posted from TSR Mobile

Yeah, draw a 2D good diagram.

Reply 2287

badaman

Original post by Ayman!

Yeah, draw a 2D good diagram.

Got any tips on integration?

Reply 2288

Kevin De Bruyne

Original post by Supermanxxxxxx

And anyone have any tips on vectors even after exam solutions I am so confused.

Posted from TSR Mobile

Practice, diagrams, know the basics and just.. do as best as you can in the other parts of the paper :s-smilie:

and attempt the extension questions too.

Original post by badaman

Got any tips on integration?

There are only so many ways you can integrate something in C4 :tongue:

maybe some substitition or factor formulae or addition or something in your formula booklet might help.. otherwise, try everything if you are stuck :tongue:

Also, if you are asked to integrate lnx, you can use by parts and integrating 1 * lnx.

Reply 2289

Lilly1234567890

Original post by Craig1998

If you ever are stuck with an integral, consider substitutions like u = x+1 for this question, it may not be clear to see the 1-1, and it may be a little longer, but it'll give you the answer.

\pi\int_0^3 \frac{x}{x+1} dx[br]u = x+1[br]du/dx = 1 leads to dx = du[br]Limits changed to 1 and 4[br][br]=\pi\int_1^4 \frac{x}{u} du[br]=\pi\int_1^4 \frac{u-1}{u} du[br]=\pi\int_1^4 1 - \frac{1}{u} du[br]=\pi[u - ln|u|]_1^4[br]=\pi(4 - ln4 - 1 + ln1)[br]=\pi(3-ln4)

Can we use long division here? Then integrate that ?

Posted from TSR Mobile

Reply 2290

Serine Soul

Original post by thad33

Sorry guys already asked but the madas exam papers, are all those questions what feature in the individual topic questions or are they different questions?

Posted from TSR Mobile

Just open the questions up and compare?

Reply 2291

Serine Soul

I've done so much Madas C4 papers in the past few days I'm getting sick of C4 :erm:

But there has been a worrying lack of questions involving differentiating a^x so I should probably practice those.

Today is maths revision day for me! :party:

Reply 2292

Kevin De Bruyne

Original post by Serine Soul

I've done so much Madas C4 papers in the past few days I'm getting sick of C4 :erm:

But there has been a worrying lack of questions involving differentiating a^x so I should probably practice those.

Today is maths revision day for me! :party:

there is so much they can ask you about a^x, if it even pops up in the end, but have fun :h:

Reply 2293

Serine Soul

Original post by SeanFM

there is so much they can ask you about a^x, if it even pops up in the end, but have fun :h:

Last year's paper involved integrating it at the end lmao

Maybe it won't come up this year :awesome:

Still gonna practice either way :yes:

Reply 2294

EricPiphany

Original post by Lilly1234567890

Can we use long division here? Then integrate that ?

Posted from TSR Mobile

Yes.

Reply 2295

EricPiphany

Original post by Lilly1234567890

Can we use long division here? Then integrate that ?

Posted from TSR Mobile

Try integrate something like

\displaystyle \int \! \frac{x}{(x+1)^3} \, \mathrm{d}x

though.

Reply 2296

Zacken

Original post by Serine Soul

I've done so much Madas C4 papers in the past few days I'm getting sick of C4 :erm:

But there has been a worrying lack of questions involving differentiating a^x so I should probably practice those.

Today is maths revision day for me! :party:

There isn't anything to know beyond writing

a^x = e^{x \ln a}

and then using your normal knowledge to integrate/differentiate

e^{\alpha x}

where

\alpha = \ln a

in this case.

Reply 2297

thenextchemist

Original post by EricPiphany

Try integrate something like

\displaystyle \int \! \frac{x}{(x+1)^3} \, \mathrm{d}x

though.

Wouldn't that be just partial fractions?

Posted from TSR Mobile

Reply 2298

Pi/2

Please head over to my new website http://app.bubblemaths.com/ if you need help quick on any Maths problems, it's completely free and no sign up is required. Thanks