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    (Original post by Bhaal85)
    If you like this thread, rate it.
    here u r 5 stars
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    Thankyou sooooooooooooooo much.. my revision notes are too big to even fit in an arch folder so its good to have a condensed version to look through. There shall be repping for everyone who has made one of these sticky's.. lol.. and for anyone who feels so inclined I wouldn't mind a Politics one like this
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    (Original post by Elle)
    Thankyou sooooooooooooooo much.. my revision notes are too big to even fit in an arch folder so its good to have a condensed version to look through. There shall be repping for everyone who has made one of these sticky's.. lol.. and for anyone who feels so inclined I wouldn't mind a Politics one like this
    Apparently Im the only one who doesnt actually keep his notes for maths.... :confused:
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    (Original post by Leekey)
    Apparently Im the only one who doesnt actually keep his notes for maths.... :confused:
    lol i don't either.......
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    (Original post by Leekey)
    Apparently Im the only one who doesnt actually keep his notes for maths.... :confused:
    i never get notes!
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    (Original post by wonkey)
    lol i don't either.......
    Good good, I don't think it matter too much for maths though as you can only really revise by attempting questions. If you can't do a question then read the text book, if you can do it then move on to the next...
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    (Original post by Leekey)
    Good good, I don't think it matter too much for maths though as you can only really revise by attempting questions. If you can't do a question then read the text book, if you can do it then move on to the next...

    omg yeah snap, precisely what i've always done for maths!! lol
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    has anyone done the EDEXCEL GREEN BOOK PAST PAPER Q7 THE LAST PART OF IT (int between 5 and 1). I jsut cant get the correct answer
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    (Original post by Leekey)
    Apparently Im the only one who doesnt actually keep his notes for maths.... :confused:
    lol.. my dad's a Maths teacher so I'm usually overloaded with sheets etc. but I don't make the notes myself .. usually scribble working on a bit of paper.. forget how to do it.. and have to learn the topic over again.
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    (Original post by eddiedaboss)
    has anyone done the EDEXCEL GREEN BOOK PAST PAPER Q7 THE LAST PART OF IT (int between 5 and 1). I jsut cant get the correct answer
    is it page 199? its so hard!!
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    (Original post by tammypotato)
    is it page 199? its so hard!!
    The book questions are usually a lot harder than the past papers :rolleyes: At least that's what I find
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    (Original post by eddiedaboss)
    has anyone done the EDEXCEL GREEN BOOK PAST PAPER Q7 THE LAST PART OF IT (int between 5 and 1). I jsut cant get the correct answer
    here's how you do it.....i did it by parts (may well be easier by substitution, but I couldn't be bothered to think of one):

    let:
    u = x,
    dv/dx = (3x+1)^(-1/2)

    du/dx = 1
    v = (3x+1)^(1/2) (2) (1/3)
    v = (2/3).(3x+1)^(1/2)

    I = (2x/3).(3x+1)^(1/2) - (2/3) ∫ (3x+1)^(1/2) dx

    I = (2x/3).(3x+1)^(1/2) - (2/3).(3x+1)^(3/2) (2/3).(1/3)

    I = (2x/3).(3x+1)^(1/2) - (4/27).(3x+1)^(3/2)

    Now substitute the limits in:

    I = [ (10/3)(√16) - (4/27)(√16³) ] - [ (10/3)(√4) - (4/27)(√4³) ]

    I = (40/3) - (256/27) - (4/3) + (32/27)

    I = (36/3) - (224/27)

    Therefore, I = 100/27
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    what about vectors bhaal?thats a huge topic at p3!
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    (Original post by IntegralAnomaly)
    what about vectors bhaal?thats a huge topic at p3!
    I'll have a go.

    You need to be able to do:

    diagrams with directed line segments (lines in the direction of a vector with the length representing the magnitude

    unit vector notation (i and j)

    the modulus of a vector is its magnitude

    adding vectors using triangle law etc

    finding a midpoint

    These haven't come up in exams before but they might. It is easy marks as long as you know these few things. There is som stuff in the book about proving vectors are non-parallel. It is not worth the effort as you can just show that they have different gradients.


    Three Dimensions

    Here is the important stuff

    pythagoras in 3D: n = root(x^2 + y^2 + z^2) when x,y andd z are the different directions
    This gives the modulus (magnitude) of the vector

    The unit vector of the third dimension is k

    The dot product: a.b = |a||b|[email protected]
    What this means is that the scalar product of two vectors is the product of their magnitudes multiplied by the angle between them. It is important to recognise that the dot product is a number (scalar quantity) and not a vector.
    The dot product of two perpendicular vectors is zero. This is because cos90 is zero.

    DOT PRODUCT IS IN EVERY EXAM PAPER WITHOUT FAIL. REVISE IT!!!

    Projection: all you need to know is the formula a.b/|b| = the projection of a on b. It is worth doing a few practice questions from the heinemann book on projections just in case it comes up

    Vector equation of a straight line. This is mainly a notational issue. a straight line is given by r=a[email protected]b where @ is a scalar parameter.
    What this means is the the start at position vector a and there is a vector from that point in direction b with magnitude @|b|.

    It can be written in unit vectors as r= xi+ yj + zk + @(li + mj + nk)

    This can in turn be written as

    ([email protected])i + ([email protected])j + ([email protected])k

    If you have two lines and you want to prove they intersect then you must write them both in the above form. You must then compare the coefficients of i, j and k and prove there are value for the constants which will satisfy all three of the simultaneeous equations. If it does not satisfy all three then the two lines do not intersect.

    When doing dot products of these unit vector forms you only dot product the directions as this is what makes them perpendicular

    when doing dot product of (xi + yj + zk).(li + mj + nk) the result will be xl + yn + zn. This is because i,j and k are perpendicular and thus have the dot product between them of zero. you can only get a result from multiplying coefficients of like unit vectors. They might give you some kind of geometry question based on vectors but they tend to bee reasonable straight-forward. On Jan 2004 paper it was working out the area of a right triangle as the last part of question 8 so I guess that's as hard as it gets and if you know aall this stuff theen it's easy)

    That's pretty much everything you need if I remember correctly. I hope it's helpful (there may be the odd silly mistake I've made)

    Finally, Always underline vectors in the exam to show that they're vectors rather than scalar quantities. This includes unit vectors. Don't drop marks stupidly.

    MB
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    someone did a good revision topic for vectors here:

    vectors
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    For integration by parts it is useful to remember the following order of priority of u:

    i) lnx
    ii) x^n
    iii)e^kx

    i.e. if one factor is a log function, that must be taken as "u".
    if there is no log function but a power of x, that becomes"u".
    if there is neither a log function nor power of x, then the exp function is taken as "u".

    This way you may save alot of false starts.

    *Note that for x^2 and for any higher powers of x, you will need to integrate more than once.

    *Also note that when integrating a product such as: e^kx . sinx , you will need to integrate twice and use the substitution method that you may recall.
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    Edexcel P3, one of the mock papers with mark schemes they supply. I think my P3 isnt going too bad (!!) but this questions got me a little confused:

    Find ∫cos3xcosx dx

    In the answers they immediately say this is equal to ∫½(cos4x+cos2x)

    I keep looking but i just dont see why.
    Thanks
    John
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    theyre using this formula.
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    now why didnt i see that earlier?
    thanks a lot mate.
    • Thread Starter
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    (Original post by IntegralAnomaly)
    what about vectors bhaal?thats a huge topic at p3!
    Music Boy and Malaysian Dude, have pretty much covered it.

    What would really be appreciated however, is if someone where to create some notes on differential equations and how to set them up. If someone where to type out a question on differential equations, and go through it step by step about how to set them up, it would be great, I would, but I struggle on them and dispise them heavily.
 
 
 

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