2012 HSC Extension 2 Mathematics Solutions (1 Viewer)

kman16

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Hey carrot for question 12. d) (ii), once you found the midpoint aren't you then meant to find a cartesian expression for the locus?
Also thanks for the solutions :) Made me realise how simple some of the questions that i couldnt figure out were :(
 

Carrotsticks

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The locus is a fixed point, so there isn't an 'Equation' as you think it is (I presume you mean equation as in a curve).
 

kman16

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The locus is a fixed point, so there isn't an 'Equation' as you think it is (I presume you mean equation as in a curve).
Ahh I see. I wrote x= (u1 + u2)/2 , y=( (z-u1) + (u2-z) ) / 2 and then I eliminated u2 and left an equation in terms of y, x, u1. Do you think I might still get the two marks?
 

Nooblet94

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Carrot brah, thought you were coming to girra. totes devo when I walked out and you weren't there :(
 

visipac

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Could you please check up on 15)a)ii), isn't it meant to be four identical objects instead of three?
 

Trebla

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Ahh I see. I wrote x= (u1 + u2)/2 , y=( (z-u1) + (u2-z) ) / 2 and then I eliminated u2 and left an equation in terms of y, x, u1. Do you think I might still get the two marks?
I don't think that is correct because u1 and u2 are complex numbers (i.e. x and y still contain an imaginary part within u1, u2 and z)

I personally think that locus question is pretty dodgy or there is some sort of typo because it is obvious by inspection that since B1 and B2 are fixed then clearly their midpoint is fixed.
 

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