HSC 2016 MX1 Marathon (archive) (4 Viewers)

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leehuan

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Re: HSC 2016 3U Marathon

Few suggestions:

1. Use the fact that it's even to make (-1)^n = 1 as early as right after writing the expansion of (1-x)^n instead of at the end, because the fact this question wasn't split into parts meant that the result can be used essentially anytime.
2. Simplify the expansion of (1+x)^n - (1-x)^n earlier
3. Combined with 2 - I would've written nC0 -> nC6 to establish the pattern more clearly.
4. (Most unnecessary suggestion) Just write d^2/dx^2 in front of the LHS and the RHS in your second equation

Correction: Lol, 2x30 does not equal 15x5 (you forgot to rewrite as 12x5)

Though I didn't think too deeply myself to create a solution, so good job!
 

DatAtarLyfe

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Re: HSC 2016 3U Marathon

Feck me, i corrected the question but still wrote the wrong answer XD
 

DatAtarLyfe

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Re: HSC 2016 3U Marathon

Can someone post another question coz cbs doing probability
 

wu345

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Re: HSC 2016 3U Marathon

Nice Question! I have a feeling this isn't the quickest way of doing it, and it uses identities not in the 3u course but anyways ( I don't know how to use Latex so I took a picture instead)
http://i.imgur.com/X0pCTvs.jpg?1
 
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DatAtarLyfe

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HSC 2016 3U Marathon

Another integration question plz
I should just join the 4u integration, wtf am i doing...
 

DatAtarLyfe

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Re: HSC 2016 3U Marathon

Are you talking about the probability question
 

wu345

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Re: HSC 2016 3U Marathon

Wow! I didn't realise there was so much to this question... Thanks so much!
(for solving the polynomial q)
 

wu345

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Re: HSC 2016 3U Marathon

What about this one?
Capture.PNG

Also, if anyone is looking for a challenge (use products to sums)
Prove 64sin10sin20sin30sin40sin50sin60sin70sin80sin90=3/4 (angles in degrees)
 

DatAtarLyfe

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Re: HSC 2016 3U Marathon

You should at the very least show us your answer lol
im pree sure i did it wrong, coz he posted the same question in the 4u marathon but made us consider e^itheta, so am not sure how you can use 3u to solve this.
My ways soo abstract its gonna baffle even him XD
 

InteGrand

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Re: HSC 2016 3U Marathon

im pree sure i did it wrong, coz he posted the same question in the 4u marathon but made us consider e^itheta, so am not sure how you can use 3u to solve this.
My ways soo abstract its gonna baffle even him XD
There's a way to do it via trig. identities, wu345 posted a picture of his solution in a previous post.
 
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