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HSC 2016 MX1 Marathon (archive) (6 Viewers)

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Drsoccerball

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Flop21

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Flop math question thread

If anyone could help me with the questions I post in this thread, I would be super grateful (sorry in advance for stupid questions).

They will be 2u + 3u questions.

Thanks!
 

Flop21

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Re: Flop math question thread

How do you factorise "x^4 -5x^2 + 4"
 

drsabz101

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Re: Flop math question thread

Okay so u can use the cross method to get: ( x^2 - 4) (x^2-1)

then u use the difference of 2 squares i.e. (a+b)(a-b) = (a^2-b) to further factorise : (x^2-1) into (x+1)(x-1) and (x^2 -4) into (x+2)(x-2)
 
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Drsoccerball

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Re: Flop math question thread

How do you factorise "x^4 -5x^2 + 4"
2 Unit method:
Let u = x^2 solve the results and present it in the form :



If it's not integers then expand the brackets you think will cause integers.
 
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leehuan

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Re: Flop math question thread

Watch out for quadratics. Expressions reducible to quadratics. Always.
 

Flop21

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Re: Flop math question thread

2 Unit method:
Let u = x^2 solve the results and present it in the form :



If it's not integers then expand the brackets you think will cause integers.
Perfect, thanks!
 

BlueGas

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Re: Flop math question thread

Are you preparing for uni?
 

Flop21

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Re: Flop math question thread

How do you get the answer to this:

lim x->1 (x^3 -1)/(x^2 -1)

The answers say 3/2. I understand how to do these but I keep getting 2, so going wrong somewhere.
 
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