2012 Year 9 &10 Mathematics Marathon (3 Viewers)

kazemagic

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Re: 2012 Year 9 &10 Mathematics Marathon

first one is probably 200
for the 2nd one that ramp line, does it intersect the parabola 2 times?
 

kazemagic

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Re: 2012 Year 9 &10 Mathematics Marathon

for question 2 is it 19.5? it's probably wrong lol
 

Carrotsticks

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Re: 2012 Year 9 &10 Mathematics Marathon

Haha that's so cute, a 'mushroom ornament'.
 

Fawun

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Re: 2012 Year 9 &10 Mathematics Marathon

I have a feeling that my answer is incorrect but here is attempt:





I find Latex confusing and time consuming to use so I decided to write it out. Sorry if you can't read my handwriting.
 

Ealdoon

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Re: 2012 Year 9 &10 Mathematics Marathon

^ You have very neat handwriting.
 
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Re: 2012 Year 9 &10 Mathematics Marathon

I have a feeling that my answer is incorrect but here is attempt:





I find Latex confusing and time consuming to use so I decided to write it out. Sorry if you can't read my handwriting.
Your solution is right, however the final answer is actually to 3 sig figs, or

try to keep your working in exact form and round off only in the end

otherwise, correct!

also, definitely very nice handwriting :)
 
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ymcaec

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Re: 2012 Year 9 &10 Mathematics Marathon

Your solution is right, however the final answer is actually to 3 sig figs, or

try to keep your working in exact form and round off only in the end

otherwise, correct!

also, definitely very nice handwriting :)
actually she forgot to minus the small cone
 

Demento1

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Re: 2012 Year 9 &10 Mathematics Marathon

actually she forgot to minus the small cone
Well spotted, I was thinking there was something incorrect with that solution based on the final answer.
 

kazemagic

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Re: 2012 Year 9 &10 Mathematics Marathon

Eliminate theta from the following expressions:

omg lol just saw this question in the 2u jb fitzpatrick book. Page 174 Q.11

I came back wanting to cheat, seems like I can't find the worked solution for this question in this thread :/
 

Demento1

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Re: 2012 Year 9 &10 Mathematics Marathon

omg lol just saw this question in the 2u jb fitzpatrick book. Page 174 Q.11

I came back wanting to cheat, seems like I can't find the worked solution for this question in this thread :/
If I recall correctly from what Carrot has said, this is the proof you can use to show the equation of an ellipse.
 

iBibah

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Re: 2012 Year 9 &10 Mathematics Marathon

omg lol just saw this question in the 2u jb fitzpatrick book. Page 174 Q.11

I came back wanting to cheat, seems like I can't find the worked solution for this question in this thread :/
Yeh it's also in Cambridge, quite common actually.

If I recall correctly from what Carrot has said, this is the proof you can use to show the equation of an ellipse.
Correct (though not a 'proof' rather a derivation)

Try with x=cosa and y=sina and you get the unit circle essential to trig.
 

kazemagic

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Re: 2012 Year 9 &10 Mathematics Marathon

k i got it, had to use trig identity tho :/ don't know how u guys got it without using it
 

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