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    Hi.
    For question 1 what integration method should i be using.
    https://5c59854d0ccd29d489c9e5e689a8...20C4%20OCR.pdf
    thanks
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    (Original post by SamuelN98)
    Hi.
    For question 1 what integration method should i be using.
    https://5c59854d0ccd29d489c9e5e689a8...20C4%20OCR.pdf
    thanks
    No set one, there's a variety of methods. You could expand out and say \int \sin x + \sin x \cos x \, \mathrm{d}x = -\cos x + \frac{\sin^2 x}{2} + \mathcal{C} by inspection or \int \sin x + \sin x\cos x \, \mathrm{d}x = -\cos x - \frac{\cos^2 x}{2} + \mathcal{C} by inspection or note that \sin x\cos x = \frac{\sin 2x}{2}, or use the substitution u = \cos x on the latter half of the integral, or u = \sin x, etc...
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    (Original post by SamuelN98)
    Hi.
    For question 1 what integration method should i be using.
    https://5c59854d0ccd29d489c9e5e689a8...20C4%20OCR.pdf
    thanks
    Expand and use the identity:

    \displaystyle \sin 2A \equiv 2\sin A \cos A
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    (Original post by Zacken)
    No set one, there's a variety of methods. You could expand out and say \int \sin x + \sin x \cos x \, \mathrm{d}x = -\cos x + \frac{\sin^2 x}{2} + \mathcal{C} by inspection or \int \sin x + \sin x\cos x \, \mathrm{d}x = -\cos x - \frac{\cos^2 x}{2} + \mathcal{C} by inspection or note that \sin x\cos x = \frac{\sin 2x}{2}, or use the substitution u = \cos x on the latter half of the integral, or u = \sin x, etc...
    Sorry , could how explain how you got (cos^2)(x)/2 ,is that the reverse chain rule?
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    (Original post by SamuelN98)
    Sorry , could how explain how you got (cos^2)(x)/2 ,is that the reverse chain rule?
    Yeah.
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    (Original post by Zacken)
    Yeah.
    Hey.
    Would you be able to help me understand what is meant in question 8.
    I cant visualize what is mean by point c lies on l2 such that AC is perpendicular to BC.
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    (Original post by SamuelN98)
    Hey.
    Would you be able to help me understand what is meant in question 8.
    I cant visualize what is mean by point c lies on l2 such that AC is perpendicular to BC.
    Crap drawing:


    Green is line 1, blue is line 2.
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    Zacken Is it possible to use integration by parts with this?
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    (Original post by Zacken)
    Crap drawing:


    Green is line 1, blue is line 2.
    Thanks.
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    (Original post by Don Pedro K.)
    Zacken Is it possible to use integration by parts with this?
    Yep, that's definitely another method.
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    (Original post by Zacken)
    Yep, that's definitely another method.
    Ah okay thank you!

    Oh yeah this is a bit random but, assuming that you did (which I think you did), how you find last year's C3 paper? I've heard complaints about it but was it really that bad?
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    (Original post by Don Pedro K.)
    Ah okay thank you!

    Oh yeah this is a bit random but, assuming that you did (which I think you did), how you find last year's C3 paper? I've heard complaints about it but was it really that bad?
    No worries.

    Seemed fairly standard to me. :dontknow:
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    (Original post by Zacken)
    No worries.

    Seemed fairly standard to me. :dontknow:
    Would you say that the papers generally get harder (even if only a bit) from the earlier ones to the later ones?
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    (Original post by Don Pedro K.)
    Would you say that the papers generally get harder (even if only a bit) from the earlier ones to the later ones?
    Erm, I wouldn't really say so, no. They seem to fluctuate in difficulty, some of the recent ones area easier, most are standard, some are harder.
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    (Original post by Zacken)
    Erm, I wouldn't really say so, no. They seem to fluctuate in difficulty, some of the recent ones area easier, most are standard, some are harder.
    Ah okay awesome, thanks Zacken! Best of luck with things.
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    (Original post by Don Pedro K.)
    Ah okay awesome, thanks Zacken! Best of luck with things.
    No problem, good luck to you too!
 
 
 
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