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    I managed to do part A and I attempted part B but I can't tell where I went wrong with it:




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    (Original post by creativebuzz)
    I managed to do part A and I attempted part B but I can't tell where I went wrong with it:




    So you have det(P)=2P^2 - P

    Then use the formula : area of image = area of object x det(P)
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    (Original post by stardude8)
    So you have det(P)=2P^2 - P

    Then use the formula : area of image = area of object x det(P)
    Oh okay!

    So where did I go wrong here:

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    (Original post by creativebuzz)
    Oh okay!

    So where did I go wrong here:

    det (p) does not equal 1/(2p^2 - p) , but simply 2p^2 - p. You only use the reciprocal when finding the inverse matrix, which you are not doing here.
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    (Original post by stardude8)
    det (p) does not equal 1/(2p^2 - p) , but simply 2p^2 - p. You only use the reciprocal when finding the inverse matrix, which you are not doing here.
    Ah thank you! (Positive rating for being such a help )!

    Would you mind helping me on this question?




    I managed to get the 'show' part of the question, but this is as far as I got for the second part of the question!
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    (Original post by creativebuzz)
    Ah thank you! (Positive rating for being such a help )!

    Would you mind helping me on this question?




    I managed to get the 'show' part of the question, but this is as far as I got for the second part of the question!
    First make sure you're using the correct line equation from the question - the last t should be squared.

    So you know the general equation of a circle is (x-a)^2 +(y-b)^2 = r^2 . Substitute in your 3 coordinates into these equation, and as the radius is always the same, you can set two of the equations to be equal to one another.
    E.g. with
    (0,0) (0,at)
    (0-a)^2 +(0-b)^2 =a^2 +b^2 =r^2
    (0-a)^2 +(at-b)^2=a^2 + (at)^2 -2atb+b^2=r^2

    They both equal r^2, so put them together and solve for b. Do the same with another two coordinates to find a

    N.B. (a,b) would then be the centre of the circle.
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    You got really neat handwriting. #Jealous
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    (Original post by Tiri)
    You got really neat handwriting. #Jealous
    Ahah, that's actually my handwriting when I'm rushing but thank you #appreciative
 
 
 
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