2U 2015 Discussion Thread (1 Viewer)

thomasdo1

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Im confused about q16 i) do you simply write similar triangles? I lost 9-11 marks.
I wrote 100% working out on every question due to paranoia haha, used AAA similarity cause the top and base of a cylinder is parallel
 

dylanmcgirr

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I think i got either 94/95, anyone know how this will do as an examination mark? paper seemed OK so maybe the same?
 

thomasdo1

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for 15 c) ii] and iii] , I simplified 80/0.5 to be 40 instead of 160

would I get 1/2 for ii] and 0/1 for iii]

or since the concept was right, would it be 1/2 for ii] and 1/1 for iii]?
 

Mythos

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if you didn't write similar triangles for q16c (i) do you lose a mark? i just equated the ratios :/
 

Mr_Kap

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What made you guys think similar triangles.

For me: i initially though of trying pythagoras and some other shit. It was only right at the end i saw the similar triangles and by that time it was too late for me to do the question in 30 seconds.
 

SlimiJay

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What made you guys think similar triangles.

For me: i initially though of trying pythagoras and some other shit. It was only right at the end i saw the similar triangles and by that time it was too late for me to do the question in 30 seconds.
i did exactly what you did tried using pythagoras but then i said to my self this is to easy to see for a 16 so i split it up and realised the similarities hahah

what do you reckon 88 raw will align to btw?
 

invisible036

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there was a similar question in the Cambridge Yr11 3U book iirc, and when i saw 16c similar triangle pops into my head immediately.
 

I97

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What made you guys think similar triangles.
I did Q10b of the 2010 Sydney Grammar trial yesterday and it was a VERY similar question which required the same approach and making similar triangles seemed the most straight forward way of eliminating 'y'.
 

invisible036

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i did exactly what you did tried using pythagoras but then i said to my self this is to easy to see for a 16 so i split it up and realised the similarities hahah

what do you reckon 88 raw will align to btw?
maybe low 90s, around 93?
 

keepLooking

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I did Q10b of the 2010 Sydney Grammar trial yesterday and it was a VERY similar question which required the same approach and making similar triangles seemed the most straight forward way of eliminating 'y'.
I spent 30 minutes on it until I remembered that paper. I am extremely glad that I went through Q16/10's.
 

Pab

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What made you guys think similar triangles.

For me: i initially though of trying pythagoras and some other shit. It was only right at the end i saw the similar triangles and by that time it was too late for me to do the question in 30 seconds.
I made this more complicated than it should have been. I did the area of the rectangle HR = 1/2(HR) + xy + 1/2(x)(H-y) + 1/2(y)(R-x) then rearranged for y. Also tried pythagoras and i was like wtf so i stopped.
 

thomasdo1

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If you're doing 4u next year, what happens if your 4u aligned is scaled less than your 2u? Are you allowed to choose your 2u mark over your 4u mark?
 

photastic

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Anyone got the paper? Wanna compare but word from students and they said it was not hard.
 

kenny777777

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What made you guys think similar triangles.

For me: i initially though of trying pythagoras and some other shit. It was only right at the end i saw the similar triangles and by that time it was too late for me to do the question in 30 seconds.
Wrote down the eqn of the Volume of the cylinder and compared it to the one that they gave us. Noticed that their answer didn't have a 'y' but R and H instead, so u had to find an eqn that related y to R and H. Similar triangles took me a minute to figure out maybe cause its similar to rates of change Qs in 3u.
 
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