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Edexcel A2 C4 Mathematics June 2016 - Official Thread Watch

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    (Original post by joodaa)
    do we need to know how to integrate/differentiate arccosx arcsinx and arctanx?
    Not for C4 no. FP3 yes
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    (Original post by Supermanxxxxxx)
    Attachment 542363
    I just don't understand what's happened on step 2 of 8b


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    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

u = x+1

du/dx = 1 leads to dx = du

Limits changed to 1 and 4



=\pi\int_1^4 \frac{x}{u} du

=\pi\int_1^4 \frac{u-1}{u} du

=\pi\int_1^4 1 - \frac{1}{u} du

=\pi[u - ln|u|]_1^4

=\pi(4 - ln4 - 1 + ln1)

=\pi(3-ln4)
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    (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
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    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?


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    (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

u = x+1

du/dx = 1 leads to dx = du

Limits changed to 1 and 4



=\pi\int_1^4 \frac{x}{u} du

=\pi\int_1^4 \frac{u-1}{u} du

=\pi\int_1^4 1 - \frac{1}{u} du

=\pi[u - ln|u|]_1^4

=\pi(4 - ln4 - 1 + ln1)

=\pi(3-ln4)
    Cheers brah I was thinking of doing that but didn't believe it would work


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


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    (Original post by Supermanxxxxxx)
    And anyone have any tips on vectors even after exam solutions I am so confused.


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    Yeah, draw a 2D good diagram.
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    (Original post by Ayman!)
    Yeah, draw a 2D good diagram.
    Got any tips on integration?
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    (Original post by Supermanxxxxxx)
    And anyone have any tips on vectors even after exam solutions I am so confused.


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    Practice, diagrams, know the basics and just.. do as best as you can in the other parts of the paper 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 maybe some substitition or factor formulae or addition or something in your formula booklet might help.. otherwise, try everything if you are stuck

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

u = x+1

du/dx = 1 leads to dx = du

Limits changed to 1 and 4



=\pi\int_1^4 \frac{x}{u} du

=\pi\int_1^4 \frac{u-1}{u} du

=\pi\int_1^4 1 - \frac{1}{u} du

=\pi[u - ln|u|]_1^4

=\pi(4 - ln4 - 1 + ln1)

=\pi(3-ln4)
    Can we use long division here? Then integrate that ?


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    (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?


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    Just open the questions up and compare?
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    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:
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    (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:
    :lol: there is so much they can ask you about a^x, if it even pops up in the end, but have fun
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    (Original post by SeanFM)
    :lol: there is so much they can ask you about a^x, if it even pops up in the end, but have fun
    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:
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    (Original post by Lilly1234567890)
    Can we use long division here? Then integrate that ?


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    Yes.
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    (Original post by Lilly1234567890)
    Can we use long division here? Then integrate that ?


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    Try integrate something like \displaystyle \int \! \frac{x}{(x+1)^3} \, \mathrm{d}x though.
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    (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.
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    (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?



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    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
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    (Original post by Bloom77)
    Wouldn't that be just partial fractions?



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    Wouldn't a substitution work?
 
 
 
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