2012 CSSA Maths 2U (2 Viewers)

iBibah

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i had the idea that limiting sum was somehow involved but i did it wrong.

whats the reason why r=3/7x4/7?
Because the probability of Sophie winning is:

 

Kimyia

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That circle question is the reason why you learn the proofs and derivations of things instead of rote learning :p (at mx1 kids)

Most mx1 students should have seen the proof before.
yeah, i noticed the rule we learnt in mx1 but i think all you had to do was equate two equations to prove it....?
 

iBibah

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Can you (or anyone else) post up the probability question?
There are 4 red discs and 3 black discs in bag. Sophie and Emma play a game where they each have a turn at drawing a disc with replacement. Sophie starts.

Sophie wins when she draws a red disc and Emma wins when she draws a black disc.

(i) What's the probability that Sophie wins on the first draw?

(ii) What is the probability that Sophie wins in the first 3 draws. (either 3 or less)

(iii) What is the probability that Sophie wins the game
 

iBibah

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Re: Thoughts on CSSA 2U Mathematics Exam??

I think it was 15 (a)....it was that cylinder one, proving the h
The only way I saw was to prove both triangles were similar than use sides in ratio, which was stupid for 2 marks.
 

iBibah

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yeah, i noticed the rule we learnt in mx1 but i think all you had to do was equate two equations to prove it....?
Yeh not sure why so many got stuck when you found HK^2 twice, clearly you had to use it. People seem to forget that when they help you through a question, most likely every part will be used again in another part.
 

rsagar

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Re: Thoughts on CSSA 2U Mathematics Exam??

Q15 and Q16 was done poorly by me...

I think out of 30. I probably got 9 or 10.
That's like dropped from 100 to 80 + extra errors might have not picked up
= 70-75/100 AH SHIT !!! There's goes my HSC :bomb: :punch:
 

Kimyia

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Re: Thoughts on CSSA 2U Mathematics Exam??

The only way I saw was to prove both triangles were similar than use sides in ratio, which was stupid for 2 marks.
yep, i did something along those lines. but i left that question to the very end so kinda rushed it :\
 

Kimyia

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What were the solutions for the Q16 a velocity/time graph?
ooh, that was another question i really didnt get. they asked you what the velocity was at t=3 but you could only estimate (right?)
 

iBibah

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ooh, that was another question i really didnt get. they asked you what the velocity was at t=3 but you could only estimate (right?)
Not really the graph was supposed to cut the x-axis at t=3. Hence the velocity was 0 at that point.
 

Kimyia

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Not really the graph was supposed to cut the x-axis at t=3. Hence the velocity was 0 at that point.
grrr. i think i wrote something like it was approaching zero, but was close to like -0.5 or something. silly graph did not cross at t=3 :\ (...that or i was overthinking it)
 

Kostie100

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grrr. i think i wrote something like it was approaching zero, but was close to like -0.5 or something. silly graph did not cross at t=3 :\ (...that or i was overthinking it)
I said velocity was 0 as well but it didn't look like exactly 0... stupid CSSA
 

MATHmaster

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What was the answer to Q9 Multiple Choice: the one with the triangle with interior angle of (180-B) [once you use the angle sum of straight line to get there]
I used the sine rule but I'm not fully sure...
 

UTRazilBay

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What did u guys get for the find the values of a,b and c. It was in an equation where instead of an equal sign their was a congruency sign
 

Kimyia

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What was the answer to Q9 Multiple Choice: the one with the triangle with interior angle of (180-B) [once you use the angle sum of straight line to get there]
I used the sine rule but I'm not fully sure...
I think i said A because i thought sin(180-B) = -cos(B) and so used the sine rule with a + instead of a - to account for my negative angle. but hey, could be completely wrong :D

...thinking about it now, my reasoning seems completely wrong. oh well, one less mark
 
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