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    (Original post by NotNotBatman)
    For the volume on 7b I got something like V=\frac{1637}{5}\pi
    'Twas 544pi - 1024(pi)/5 = 1696(pi)/5
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    (Original post by NotNotBatman)
    For the volume on 7b I got something like V=\frac{1637}{5}\pi
    I got same as you.
    EDIT: nvm my bad
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    Hi guys i really need some help with this, i'm panicing so hard..

    for question 4 i accidently put the x on the top instead of the bottom so differentiated and got -x^2 / 5 = t + c

    then everything else i did was from this. So i think i got both of the questions wrong. My methodology was correct but i got the wrong equation because I made this silly error.

    I ended up getting 640 as t and did 640x24x60 to get the minutes

    How many marks would i lose for this? Would i get any marks carried forward?

    for the very last vector question i used 1/2absinC to get the area but used 1/2(2route5)(2route5)(3/5) instead of using 2route2 so i got 6 instead of 12/5 for the area.

    For the very last section I used P +/- linda(direction vector of l2) to work out the two points of B but worked out linda as 1 which is wrong.

    How many marks in total would i lose for these errors? Any help would be very appreciated!
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    was the parametric x = 4 tant and y = 5root(3)sin2t
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    Anyone know how many marks would be lost for misreading the volume question as an area? I'm thinking all 4 lost.
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    I differentiated -cos (piy) wrong , didnt take the pi out. If my whole dy/dx is correct expect im missing the pi how much marks should i lose ... it was a 6 marks question i guess
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    (Original post by Don Pedro K.)
    'Twas 544pi - 1024(pi)/5 = 1696(pi)/5
    The 544 looks right, I can't remember the fraction though, what was the curve equation?
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    Wasn't the area of the whole rectangle thing 512 pi?
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    (Original post by edothero)
    Let E be a general point on the line l_{2}

    So \mathbf{r} = \begin{pmatrix} 1-5\lambda \\ 5+4\lambda \\  2+3\lambda \end{pmatrix}

    Find PE:

    \vec{PE} = \begin{pmatrix} 1-5\lambda \\ 5+4\lambda \\ 2+3\lambda \end{pmatrix} - \begin{pmatrix} 1 \\ 5 \\ 2 \end{pmatrix}

    So \vec{PE} = \begin{pmatrix} -5\lambda \\ 4\lambda \\ 3\lambda \end{pmatrix}

    Now we know that \vec{AP} = \vec{PE}

    Therefore the lengths are the same, as the length of \vec{AP} = 2\sqrt{2}

    You know that |\vec{PE}| = \sqrt{(5\lambda)^{2} + (4\lambda)^{2} + (3\lambda)^{2}} = 2\sqrt{2}

     \sqrt{50\lambda^{2}} = 2\sqrt{2}

    50\lambda^{2} = 8

     \lambda = \pm \dfrac{2}{5}

    Then use this lambda with the general point equation \mathbf{r} = \begin{pmatrix} 1-5\lambda \\ 5+4\lambda \\ 2+3\lambda \end{pmatrix}
    Lol, lost all 5 marks on that question...shame
    Also for the value of lambda that I obtained was 32, I know this is wrong know but everything else I got was correct.
    Do you think the error will be carried forward to the next question.
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    (Original post by Aruba852)
    I differentiated -cos (piy) wrong , didnt take the pi out. If my whole dy/dx is correct expect im missing the pi how much marks should i lose ... it was a 6 marks question i guess
    It was 5 marks for the dy/dx and 4 marks for the coordinates. I also got the dy/dx wrong but I reckon we will definitely get some method marks!
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    (Original post by NotNotBatman)
    The 544 looks right, I can't remember the fraction though, what was the curve equation?
    Y = (2x-1)^(3/4) I believe?
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    http://www.thestudentroom.co.uk/show...3#post66069183 - Please vote!
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    (Original post by coolguy123456)
    Wasn't the area of the whole rectangle thing 512 pi?
    We wanted volume not area
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    OH GOD YES! After doing misreably in C3, I made up for it in c4!!!! 71-73/75. FEELSGOODMAN
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    Any idea how many marks 6. b), c), d), & 8. a) were worth?
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    Hi guys
    On Q3 I forgot the minus 2 and got an answer of 6/22+π instead of 8/22+π. This lead to my next part being wrong also. Bow many marks do you think I'll loose. All of them?

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    (Original post by edothero)
    Spoiler:
    Show
    Let E be a general point on the line l_{2}

    So \mathbf{r} = \begin{pmatrix} 1-5\lambda \\ 5+4\lambda \\  2+3\lambda \end{pmatrix}

    Find PE:

    \vec{PE} = \begin{pmatrix} 1-5\lambda \\ 5+4\lambda \\ 2+3\lambda \end{pmatrix} - \begin{pmatrix} 1 \\ 5 \\ 2 \end{pmatrix}

    So \vec{PE} = \begin{pmatrix} -5\lambda \\ 4\lambda \\ 3\lambda \end{pmatrix}

    Now we know that \vec{AP} = \vec{PE}

    Therefore the lengths are the same, as the length of \vec{AP} = 2\sqrt{2}

    You know that |\vec{PE}| = \sqrt{(5\lambda)^{2} + (4\lambda)^{2} + (3\lambda)^{2}} = 2\sqrt{2}

     \sqrt{50\lambda^{2}} = 2\sqrt{2}

    50\lambda^{2} = 8

     \lambda = \pm \dfrac{2}{5}

    Then use this lambda with the general point equation \mathbf{r} = \begin{pmatrix} 1-5\lambda \\ 5+4\lambda \\ 2+3\lambda \end{pmatrix}
    Interesting.

    I wrote because mod l2's direction = 5sqrt2 and we want lengths of +-2sqrt2, then we must multiply the line equation direction by factors of +-2/5
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    (Original post by MrPooey)
    Anyone know how many marks would be lost for misreading the volume question as an area? I'm thinking all 4 lost.
    I did thr same mistake lol. I even had to integrate that function again. Hope i read it right that time altho pretty sure area is correct. I think we can get 2 if area is correct :/

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    For 7b, I rushed the last part and wrote 1024pi(/5) -544pi instead of 544pi -1024pi/5 :/

    How many marks lost on this?
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    how many marks was question 3 and the last part of 7 worth?
 
 
 
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