2006 HSC Mathematics Solutions (1 Viewer)

skyline

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where de hec u gettin cosine rule for dat qn from, u juz take the angle from 180 degrees and den dat gives u angle DBA hence angle B= angle A since base angles of isoceles r equal den for length of BD you use L=radius times the angle from angle B... duz any1 else agree, correct me if im wrong????:rofl:
 

ggarfag

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Thanx for putting up the solutions .. the answer for 10 b v) - the minimum area is 32(root)3 cm^2, but i don't remember part iv).

Also with question one - ur calculator was in radians, so the angle in part d is wrong.. it should be 18 degrees (nearest degree) not 35 degrees.
 

fishy89sg

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im pretty sure the vertex for Q9 a is (3, -1) hence the focus is (3, 2)

cause its

12y = x^2 - 6x - 3

add 12 to both sides

12y + 12 = x^2 - 6x + 9
12(y+1) = (x-3)^2


is it
 

Loz_metalhead

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That's what I got. There's another thread where people said they also got (3,2)
 

T.Goodhew

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Yes, of course your correct... i'll ammend the solutions asap, thanks for bringing it to my attention.
 

T.Goodhew

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Okay guys, all the errors brought up so far have been incorporated into the solutions... and now we have solutions v.1.1 :D
 

insanerp

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lol you didn't need to use the quadratic formula on 9 (b) (i).
it seems i got question 8 (b) (ii) wrong when i was so sure i got it right :(
guess i'll just fail life now huh :p
 

rusty123

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dude just pointing out your solution to 7b iii) is wrong. in the first set of brackets in the third line, you had sin(2pi/3) as (2pi - root3)/2, whereas it should only be (root3)/2 so the answer comes out being 7.4 or so i think. also, an answer for 6a iii), the prove it's a rhombus one, would be great as i'm unsure about it. oh and in question 6b iii), i put the limiting value as 450 cause it only decreases from this initial value. i had never seen the term "limiting value" with regards to exponential growth/decay before so i assumed it was asking for the limit of how high the population gets. does this seem reasonable enough to get the mark? or am i way off track... thanks anyone who replies
 
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sanjay_88

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DUDES!!!! Seriously, why bother doin this!!?!? Regardless of what u do frm now on, u CANNOT change anything about wat u did, so stuff it. Go out and hav some fun, all year 12's deserve to enjoy life now(after all exams are done of course)
 

jfan30

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hey Goodhew, with question 4C it doesnt say specifically that the girl does not put the chess pieces back after she picks them.. so doesnt t that mean the probability of chosing a colour at any time is 0.5? write back asap pls
 

kido_1

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yes it is non-replacement probability, SHE DOES NOT PUT THE CHESS PIECES BACK!!!
That was confirmed by my mathematics teacher. I know a really smart girl who lost 4 marks in that probability.
Silly mistakes these days(I lost like 3-10, am I bad)
 

jfan30

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in the probability question is doesnt specify whether she puts the pieces back or not. like what if she just picks one but doesnt actually take it away. thats what im trying to say. BOS should excuse that question
 

T.Goodhew

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Yeah unfortunately made some silly errors, but cleared most up i think... what else do you expect when you do the HSC at midnight lol
 
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dunno04

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T.Goodhew said:
Yeah unfortunately made lots of silly errors, but cleared most up i think... what else do you expect when you do the HSC at midnight lol
lol
yesh...u need to be really alert to do it.
Or else u will do some of the dumbest mistake ever.
xD
 

T.Goodhew

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rusty123 said:
dude just pointing out your solution to 7b iii) is wrong. in the first set of brackets in the third line, you had sin(2pi/3) as (2pi - root3)/2, whereas it should only be (root3)/2 so the answer comes out being 7.4 or so i think. also, an answer for 6a iii), the prove it's a rhombus one, would be great as i'm unsure about it. oh and in question 6b iii), i put the limiting value as 450 cause it only decreases from this initial value. i had never seen the term "limiting value" with regards to exponential growth/decay before so i assumed it was asking for the limit of how high the population gets. does this seem reasonable enough to get the mark? or am i way off track... thanks anyone who replies
You're absolutely right about the trig error, that's been fixed in the newest version of the solutions. I'm afraid the limiting value solution is correct however.
 

T.Goodhew

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jfan30 said:
hey Goodhew, with question 4C it doesnt say specifically that the girl does not put the chess pieces back after she picks them.. so doesnt t that mean the probability of chosing a colour at any time is 0.5? write back asap pls
The probabilities are without replacement as shown in the current version of the solutions. This is primarily because the question asks for different squares.
 
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dunno04

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T.Goodhew said:
The probabilities are without replacement as shown in the current version of the solutions. This is primarily because the question asks for different squares.
are u sure?

ohh wellz..
what can i do.
I got only one HSC.
and i 've done it.
=D
 

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