• Congratulations to the Class of 2024 on your results!
    Let us know how you went here
    Got a question about your uni preferences? Ask us here

Mathematics solutions (1 Viewer)

umz93

Member
Joined
Mar 4, 2010
Messages
350
Gender
Male
HSC
2011
Thanks, my answers were largely the same as yours. (Which is a good sign)



I don't really remember them exactly, I took the test paper home and after comparing the answers with the questions, it sort of jogs the memory a bit and you have an idea whether you got it or not!
What is 6(b)iii asking?
 

kev-is-red

Member
Joined
Oct 22, 2011
Messages
105
Gender
Male
HSC
N/A
I can't remember half of these questions, never mind what my answers were.

On a brighter note, Harold and Kumar 3 opens in cinemas on November 4 (3 days after I finish).
 
Joined
Sep 20, 2010
Messages
2,225
Gender
Undisclosed
HSC
2012
My proof for 9aii)

If AB = AC, and AD = AE (given)
Then BC is parallel to DE (equal intercept theory)

RTP triangle BCF is congruent to triangle DFE
Angle BFC = DFE (vertically opposite)
Angle FBC = FED (alternate angles in parallel lines)
Therefore triangle BCF is congruent to triangle DFE (AAA)

We know BC : DE = 1 : 2,

Hence in similar triangles BCF and DFC

BC : DE = BF : FE (corresponding sides)
Therefore BF : FE = 1 : 2

Is this reasoning correct?
I did this. I think its correct!
 

OmmU

★ BoS Deity ★
Joined
Jan 21, 2011
Messages
404
Location
Middleofnowhere
Gender
Male
HSC
2011
Uni Grad
2017
Ok with those I worked out about 107/120 :\ I can't believe I screwed up Q7 stat pt >.< OMG so easy. I copied the equation into my book wrong I think EHHHHHh!!! Ok I have to get off here and study ext1 >.<
 

umz93

Member
Joined
Mar 4, 2010
Messages
350
Gender
Male
HSC
2011
Ok with those I worked out about 107/120 :\ I can't believe I screwed up Q7 stat pt >.< OMG so easy. I copied the equation into my book wrong I think EHHHHHh!!! Ok I have to get off here and study ext1 >.<
Nice, im around 100-106 because i dont remember all my answers :/
 

nephh22

Member
Joined
May 19, 2011
Messages
125
Gender
Male
HSC
2011
that was the easiest 2marks in the whole paper (though it's hard to judge, pretty much 118 out of the 120 marks were REALLY easy, the other 2 were slightly harded)
haha yeh true... it was so easy, took like 2 seconds, so i wasnt sure if i was right lol (cause it took like 2 seconds). :L
 

nephh22

Member
Joined
May 19, 2011
Messages
125
Gender
Male
HSC
2011
I can't remember half of these questions, never mind what my answers were.

On a brighter note, Harold and Kumar 3 opens in cinemas on November 4 (3 days after I finish).
loool cant WAIT!!! I bet ur watching Harold and Kumar: Go to White Castle, as I am... :D
 

o_0

Member
Joined
Oct 2, 2011
Messages
145
Gender
Male
HSC
2011
My proof for 9aii)

If AB = AC, and AD = AE (given)
Then BC is parallel to DE (equal intercept theory)

RTP triangle BCF is congruent to triangle DFE
Angle BFC = DFE (vertically opposite)
Angle FBC = FED (alternate angles in parallel lines)
Therefore triangle BCF is congruent to triangle DFE (AAA)

We know BC : DE = 1 : 2,

Hence in similar triangles BCF and DFC

BC : DE = BF : FE (corresponding sides)
Therefore BF : FE = 1 : 2

Is this reasoning correct?
Heya this is all good, except for the first part... i don't think assuming that AB=AC and going from there is a valid proof,


the proper proof is AB:AD = 1:2, and AC:AE = 1:2, and angle[DAE] is shared. therefore, triangles ABC and ADE are similar (two pairs of sides in proportion, with included equal angle)
 

weirdguy99

Member
Joined
Mar 17, 2009
Messages
171
Location
Sydney, Australia
Gender
Male
HSC
N/A
FFFUUUUUUUUUUU...I got ln{(2I/10^-12)-(I/10^-12)} and then I proceeded to bloody cross multiply. If only I had solved it properly, I would have gotten 10ln2 instead of ln2I^2... :(
 

Gillywilly

New Member
Joined
Dec 17, 2009
Messages
25
Gender
Male
HSC
2011
hmm i thought they meant conscutive days, including 2 consecutive days as well
so i did 1 minus (probability of wearing the same shirt in 2 or 3 consecutive days)
i.e. 1 - [P(RR) + P(BB) + P(RRR)] siiiighh was a bit unclear for me :/
 

damo_g

Member
Joined
Oct 21, 2011
Messages
92
Gender
Male
HSC
2011
fuked up on 4(e) but i realised that when i first looked back over the paper. Will still get 1 mark for 1 correct inequality. Other than that everything looks good. Confident that i am 100+/120, after seeing this i think my mark should be up near 110.
 

damo_g

Member
Joined
Oct 21, 2011
Messages
92
Gender
Male
HSC
2011
Can someone shed some light on 8(b)(ii) pleaseee :)
A1 = 29227(1.005) + M(1.005)

A2 = 29227(1.005)^2 + M(1.005)^2 + M(1.005)
= 29227(1.005)^2 + M(1.005 + 1.005^2)

A3 = you get the point


An = 29227(1.005)^n + M(1.005+1.005^2+...+1.005^n)
= 29227(1.005)^n + M(a(r^n-1)/(r-1))

After 240 months An = 800000. So solve the equation when n = 240 and An = 800000. Ends up with the answer in the OP.
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top