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    (Original post by bongo fury)
    why does cot^2 2x = cosec^2 2x -1 ?
    derived from sin^2x plus cos^2x = 1
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    Its just a trig identity that you just learn.

    I think it derieves from cot x = cosx/sinx and then doing alot of fancy stuff I cant quite remember.
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    (Original post by bongo fury)
    why does cot^2 2x = cosec^2 2x -1 ?
    divide cos^2 x + sin^2 x= 1 by sin^2 x and subtract 1 from each side
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    Oh i see. Thanks
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    Please could someone explain how to do Question 4 (i) from the January 2008 paper?

    It asks you to integrate ln (x/2)

    I got xln1/2x - 1/12x^3

    But I don't think I have done it right.
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    (Original post by [email protected])
    Please could someone explain how to do Question 4 (i) from the January 2008 paper?

    It asks you to integrate ln (x/2)

    I got xln1/2x - 1/12x^3

    But I don't think I have done it right.
    Do it by parts and say that it is 1*ln(x/2)
    and so 1st*integral of second - integral of (differential of the first * integral of the second)

    this is then xln(x/2) - integral of (1/2x / 1/2x)
    so the final answer is xln(x/2) - x + c
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    whaaaaaaaaat?! how do you integrate lnx?????
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    u = lnx, dv = 1

    solve from there
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    oooh thanks!
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    Personally I learn that Int of lnx is xlnx - x + c but I know how to prove it just in case

    Do you still get all marks if you get the answer right these days? Can't remember how edexcel marking works..
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    How do you do 5a). on the C4 jan 2008? I factorise it, but i get y^2 - 24y - 128 = 0 Are there any solutions for this?
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    http://sohanshah.webs.com/mathsasalevel.htm

    Download 'Everything C4'.
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    i'm done for. C4 will be the death of me
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    Hmm I've completely skipped vectors and cba to learn it at this point in time :p:, I still figure I can get 75% + raw marks, does that warrant an A for C4 in UMS?
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    I thought 80% was an A... but not completely sure...
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    Christ im nervous about this exam. Its like they took all the hardest stuff you could possibly do in A level maths and stuck it in one rotten module. I hate it :mad:

    at least I wont have to do maths ever again after tomorrow, about time to be honest
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    What are the best parts to learn to get a mid D in this module. I.e. easiest way to ensure a D?

    Actually better make it a C just in case.

    I'm scared.
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    (Original post by Trif)
    What are the best parts to learn to get a mid D in this module. I.e. easiest way to ensure a D?

    Actually better make it a C just in case.

    I'm scared.
    Vectors, partial fractions, binomial expansion are all the easiest bits. Differentiating by parts is quite easy as well.


    I'm really struggling with differential equations
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    I cant do differential equations half the time, cause they always seem to turn it into some page long essay with only 2 useful bits of information in it and my brain gets all confused
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    cann someone plzzz tell me. if (3u^2 +3)/2 . the same as 3u^2 + 3/2

    and if so how. . january 2006 paper question 3. stuckk at simplification LOL.


    sorryy . basic algebra problemsss :mad: ..
 
 
 

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