IB Maths Marathon (1 Viewer)

davidgoes4wce

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Re: International Baccalaureate Marathon 2016

Are you sure the IB is offered by most New South Wales schools? I thought it was relatively uncommon in NSW schools.
I should have taken the word 'most' out of it. But I do know that St.Andrews Cathedral and Newington are 2 schools that offer it.
 

Nailgun

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Re: International Baccalaureate Marathon 2016

Are you sure the IB is offered by most New South Wales schools? I thought it was relatively uncommon in NSW schools.
Most rich private schools lel
 

davidgoes4wce

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Re: International Baccalaureate Marathon 2016

I also get the feeling this question has substitution and cancelling involved, would be great if somebody can get the derived working out as I spent around 15-20 minutes on the question.
 

Drongoski

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Re: International Baccalaureate Marathon 2016

I should have taken the word 'most' out of it. But I do know that St.Andrews Cathedral and Newington are 2 schools that offer it.
Trinity Grammar, MLC, Ravenswood, Kambala, Queenswood, Monte Sant Angelo, S.C.E.G.G.S. Redlands, . . . .
 
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Paradoxica

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Re: International Baccalaureate Marathon 2016








Answer: a=5, r =1.5
ar³ = 135/8 from the difference of the series.

a(1+r+r²+r³) = 205/8

1+r⁻¹+r⁻²+r⁻³ = 41/27

which is the quotient of the above two expressions.

From here, it can be solved for r⁻¹ and then a can be found.
 

davidgoes4wce

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Re: International Baccalaureate Marathon 2016

ar³ = 135/8 from the difference of the series.

a(1+r+r²+r³) = 205/8

1+r⁻¹+r⁻²+r⁻³ = 41/27

which is the quotient of the above two expressions.

From here, it can be solved for r⁻¹ and then a can be found.
You did everything right except for that last line

1+r^-1+r^-2+r^-3=65/27

It's been a long day, and you had to do the division, which correctly pointed out. This is the kind of question they put to a Year 11, I think after today I will just stick to the Haeese textbooks (which are considerably easier).
 

davidgoes4wce

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Re: International Baccalaureate Marathon 2016













From there you have to use Trial and Error to solve for r or a graphics calculating facility (where they have Equation Solver )
 
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Green Yoda

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Re: International Baccalaureate Marathon 2016

What do you reckon is harder, NSW maths or IB maths?
 

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