2012 Year 9 &10 Mathematics Marathon (2 Viewers)

Demento1

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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
You used this in your solution didn't you?



Edit: Because I imagine that's how you would work it out.
 
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Demento1

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Re: 2012 Year 9 &10 Mathematics Marathon

to revive this thread, here's a nice simple question for you guys :)

I'm suprised no one has done it after I've given some time for people. People in year 9 and 10 should seriously give the question a go. Anyways, I will spare my time to do this Q and I will be off:

Now, we can express an equation for equality in area size of triangle.







Now we know by pythagorean method that

 
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Re: 2012 Year 9 &10 Mathematics Marathon

I'm suprised no one has done it after I've given some time for people. People in year 9 and 10 should seriously give the question a go. Anyways, I will spare my time to do this Q and I will be off:

Now, we can express an equation for equality in area size of triangle.







Now we know by pythagorean method that

Correct :)

This was in Q5 of the 2005 HSC Mathematics Extension 2 Paper

(one easy mark out of 120 lol)
 

kazemagic

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Re: 2012 Year 9 &10 Mathematics Marathon

Demento such a gun O

Here's a question:
ABC is an equilateral triangle and X is a point on BC such that CX = 2BX. Prove that AX^2=7BX^2
 

Demento1

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Re: 2012 Year 9 &10 Mathematics Marathon

Demento such a gun O

Here's a question:
ABC is an equilateral triangle and X is a point on BC such that CX = 2BX. Prove that AX^2=7BX^2
When you say AX^2, do you mean:



OR



Likewise, the same goes for the 7BX^2.

The question on inspection seems straight forward (given you said equilateral triangle - tells us a lot) and although I do not have school tomorrow, I have table tennis training in the morning and I need to acquire my usual sleeping patterns unfortunately. Good night and if someone sees the Q (looking at ymcaec or anyone else), please do not hesitate to solve it.
 

Carrotsticks

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Re: 2012 Year 9 &10 Mathematics Marathon

When you say AX^2, do you mean:



OR



Likewise, the same goes for the 7BX^2.

The question on inspection seems straight forward (given you said equilateral triangle - tells us a lot) and although I do not have school tomorrow, I have table tennis training in the morning and I need to acquire my usual sleeping patterns unfortunately. Good night and if someone sees the Q (looking at ymcaec or anyone else), please do not hesitate to solve it.
Well AX is an interval but X is just a point, so obviously (AX)^2.
 

Fawun

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Re: 2012 Year 9 &10 Mathematics Marathon

I'm suprised no one has done it after I've given some time for people. People in year 9 and 10 should seriously give the question a go. Anyways, I will spare my time to do this Q and I will be off:

Now, we can express an equation for equality in area size of triangle.







Now we know by pythagorean method that

This guy is obviously going to get a 99.95 ATAR I can just see it.
 

ymcaec

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Re: 2012 Year 9 &10 Mathematics Marathon

Demento such a gun O

Here's a question:
ABC is an equilateral triangle and X is a point on BC such that CX = 2BX. Prove that AX^2=7BX^2
i used cos rule

we know that
 
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