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    (Original post by RobynDear)
    when do you know to take a constant outside of a function before you integrate??
    Constants are permitted to be 'taken out' of the integrand as you please; in other words for a constant a \in \mathbb{R}:

    \displaystyle\int af(x) \ dx = a \displaystyle\int f(x) \ dx
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    How do you choose a suitable value of x for binomial expansion? I don't understand how you know what x value to substitute in the expansion..?
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    (Original post by RobynDear)
    when do you know to take a constant outside of a function before you integrate??
    I always take the constant out before integrating, i just find it easier and sometimes i helps with the later parts of the question. I don't think it makes much difference though so do what works for you
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    (Original post by Maham88)
    haha thanks
    im on question 6c, same paper, ive got all the working out but my limits are wrong even though i got them righ in part a
    it says that its pi and 0, i have pi/2 +1 and 0....
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    (Original post by jmuz)
    sorry one more thing,

    is that a rule that could be applied to any equation in that form e.g

    integrating

    3^2u (wrt u) would therefore equal… 3^2u / 2ln3
    Yes there is a general rule at play here; some posters have mentioned it already as perhaps a result people are meant to know. When I took C4 (I took OCR, rather than Edexcel), we weren't expected to know the result per se, but perhaps the substitution. Regardless, that is what I have tried to show.
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    anyone know why theyve changed the limits from pi/2 +1, 0 to pi,0 in this question? attachment included
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    (Original post by Sumz.96)
    How do you choose a suitable value of x for binomial expansion? I don't understand how you know what x value to substitute in the expansion..?
    basically mod the x value after you've put it in the form you'll use to expand it, heres the video explaining
    http://www.examsolutions.net/maths-r...tutorial-1.php
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    (Original post by ember8)
    anyone know why theyve changed the limits from pi/2 +1, 0 to pi,0 in this question? attachment included
    pi/2 +1, 0 are coordinates of the tangent not the limits. The limits are given in the question at the start..... It's late get some sleep man maths will do this to you.
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    (Original post by ember8)
    anyone know why theyve changed the limits from pi/2 +1, 0 to pi,0 in this question? attachment included
    You have found the coordinates of the point at which the tangent is parallel to the x axis; the range in question though, is the one you want to use to evaluate the integral.
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    (Original post by MrBowcat)
    pi/2 +1, 0 are coordinates of the tangent not the limits. The limits are given in the question at the start..... It's late get some sleep man maths will do this to you.
    hahahah thanks dude, completely forgot about that
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    (Original post by Paraphilos)
    You have found the coordinates of the point at which the tangent is parallel to the x axis; the range in question though, is the one you want to use to evaluate the integral.
    haha just realised, stupid mistake!
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    (Original post by Bustamove)
    no, you wouldn't have... We shouldn't be discussing this here LOL, theres a econ thread.. but I'll try and keep it short...

    The question didn't specifiy traditional bike manufacturers.. only stated bike manufacturers which was open to interpretation.. whether you wrote about ebike manufacturers or traditional manufacturers was fine... there was a massive uproar on this on edexcel econ 3 thread. Besides, in the extracts, some traditional manufacturers were also ebike manufacturers anyway, which will just lead to a massive mess even if it were specified...
    Well, I hope you're right mate. I think I'd have gotten an a* if i were to be fully credited for my answer. Crazy considering that I had to re-learn everything within a few days
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    All papers done. Lowest i got was 71, highest was 75 in about 10 of the papers. Hopefully it'll be hard so lower boundaries so even with a mere 71 i'd get full UMS.
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    (Original post by Abdul Kalim)
    All papers done. Lowest i got was 71, highest was 75 in about 10 of the papers. Hopefully it'll be hard so lower boundaries so even with a mere 71 i'd get full UMS.
    Do you want a cookie bro?
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    How to integrate sin3xcos5x ???

    Posted from TSR Mobile
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    (Original post by Abdul Kalim)
    All papers done. Lowest i got was 71, highest was 75 in about 10 of the papers. Hopefully it'll be hard so lower boundaries so even with a mere 71 i'd get full UMS.
    :hmmmm2:
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    (Original post by Abdul Kalim)
    All papers done. Lowest i got was 71, highest was 75 in about 10 of the papers. Hopefully it'll be hard so lower boundaries so even with a mere 71 i'd get full UMS.
    ..
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    (Original post by Datta10)
    How to integrate sin3xcos5x ???

    Posted from TSR Mobile
    sin(5x+3x) =...
    sin(5x-3x) = ...

    or if you want to show off integration by parts twice (loop)
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    (Original post by TeeEm)
    sin(5x+3x) =...
    sin(5x-3x) = ...

    or if you want to show off integration by parts twice (loop)
    you can use the sum and product identities as well
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    (Original post by Maham88)
    you can use the sum and product identities as well
    what do you think my first suggestion is?
 
 
 
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