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April 26, 2025, 12:42:49 pm

Author Topic: My Suggested Solutions to SP2008 Exam 2 [Confirmed]  (Read 30718 times)  Share 

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Synesthetic

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My Suggested Solutions to SP2008 Exam 2 [Confirmed]
« on: November 11, 2008, 06:07:37 pm »
MULTIPLE CHOICE
1)D 2)E 3)B 4)E 5)B 6)C 7)D 8)D 9)B 10)C 11)D 12)A 13)E 14)B 15)D 16)C 17)A 18)E 19)C 20)E 21)A 22)B

ANALYSIS SECTION

1)a) Maximum (1,1.5)
b)i) 9x^4-26x^2+1=0
b)ii) (0.2,0.5), (1.7,1.4)
c) Graph rising steeply to maximum at (1,1.5), tapering off to around (4,1)
Mark in the previously stated inflection points at (0.2,0.5), (1.7,1.4)
d)i) 2pi*integral[(18x^3)/(3x^2+1)^2 dx,0 to 1/sqrt(3)]
d)ii) V = 2pi * integral[1/u - 1/u^2 du,1 to 2]
d)iii) V = pi[2loge(2)-1] cubic units

2)a) a=4.5 m/s^2
b) v=12 m/s
c) a=(180-3v)/40 m/s^2
d) t=1.8 seconds
e)i) From top anticlockwise, the forces are T, 100, 80g, 390
e)ii) Tcos(theta)=195sqrt(3)-100
and Tsin(theta)=979
e)iii) tan(theta)=4.118 (3 d.p.)
e)iv) T=1007 N

3)a)i) y^2=sin^2(t/3)*cos^2(t/3), via sine double angle formula
a)ii) y=±sqrt[x^2(1-x^2)], by substituting the parametric equation for x into y
b) Graph: a figure 8 on its side, symmetrical about the axes; (see Neobeo's post#6 in this thread for visualisation...
with ±1/2 instead of ±1/4 on the y-axis)
x-intercepts (-1,0), (1,0), four stationary points in each quadrant at (±1/sqrt(2),±0.5)
c) 6pi seconds
d) sqrt(2)/3 m/s
e)i) (1/3)*integral[sqrt(cos^2(t/3)+cos^2(2t/3))dt,0 to 6pi]
e)ii) 6.1 metres
(Re. 'solution' in post#6: ;D )

4)a) [(x-10)^2]/9 + (y-5)^2 = 1
b) Graph of the ellipse, endpoints clockwise from y-maximum: (10,6),(13,5),(10,4),(7,5)
Centre (10,5), semi-major axis length=3, semi-minor axis length=1
c)i) t=6 months
c)ii) 500 foxes
d)i) dy/dx=[xy-10y]/[25x-5xy] by related rates
d)ii) Use implicit differentiation to find the derivative of the given expression, such that dy/dx=[xy-10y]/[25x-5xy] in d)i)
e) Minimum number of rabbits: 6590 (to the nearest ten rabbits)
and Maximum number of rabbits: 14430 (to the nearest ten rabbits)

5)a) By conversion to polar form, sqrt(3)/2+0.5i is a root of z^3=i
b) The three roots are z={-i, sqrt(3)/2+0.5i, -sqrt(3)/2+0.5i}
c) The intersection points between the two relations are (-sqrt(3)/2, 1.5), (0,0)
d) Circle of radius=1, centre (0,1), and linear y=-sqrt(3)x
e) Shade area to the right of the linear graph, contained within the circle
f) A~2.53 square units - hamtarofreak's working: http://vcenotes.com/forum/index.php/topic,7511.msg93089.html#msg93089

======

Final edit [2]: itute confirms all these answers :)
http://www.itute.com/wp-content/uploads/2008_vcaa_specialist_mathematics_exam_2_solutions.pdf

Exam 2 mark = 93% = SAC mark :P
« Last Edit: December 12, 2008, 09:28:39 am by Synesthetic »
2007- History Revs (44)[46], Chinese SL (32)[44]
2008- English (50)[50], Literature (50)[50], Methods (49)[49.7], Specialist (44)[50.5], Chemistry (41)[45]
ENTER: 99.95

08jmy

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Re: Suggested Solutions [Pending]
« Reply #1 on: November 11, 2008, 06:09:06 pm »
these are what i got ^^

csq7

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Re: Suggested Solutions [Pending]
« Reply #2 on: November 11, 2008, 06:12:37 pm »
yay!! same :)

Nelle91

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Re: Suggested Solutions [Pending]
« Reply #3 on: November 11, 2008, 06:14:27 pm »
I had Tsintheta=784

nrisme

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Re: Suggested Solutions [Pending]
« Reply #4 on: November 11, 2008, 06:14:43 pm »
3 and 4?

deezowashington

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Re: Suggested Solutions [Pending]
« Reply #5 on: November 11, 2008, 06:20:35 pm »
stop being so arrogant plz

Neobeo

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Re: Suggested Solutions [Pending]
« Reply #6 on: November 11, 2008, 06:21:17 pm »
Since the fun is over, I'd like to mention that coblin, Ahmad and I conspired to come up with reasonable-looking yet incorrect answers. Hopefully none of you were bothered too much by it. Kudos to the various people who managed to pinpoint exactly where the errors were :P

I left the graph, since that's probably the only useful thing from it.
« Last Edit: November 11, 2008, 09:45:28 pm by Neobeo »
Mathematics Coach: Tuition and Enrichment // Email/MSN:

If you remember the flying birds, they died D=

darlok

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Re: Suggested Solutions [Pending]
« Reply #7 on: November 11, 2008, 06:21:30 pm »
Woooot lost less than 10 marks I think, 5-10 I think. Assuming I lost 2 MC's

nrisme

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Re: Suggested Solutions [Pending]
« Reply #8 on: November 11, 2008, 06:21:51 pm »
dude do u remember the question for 4c??

Synesthetic

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Re: Suggested Solutions [Pending]
« Reply #9 on: November 11, 2008, 06:22:09 pm »
I had Tsintheta=784
I can't confirm which is correct :( We'll see when others post solutions.
I'm not very confident Tsintheta=979 is correct, either, not having had time to go over the paper...
2007- History Revs (44)[46], Chinese SL (32)[44]
2008- English (50)[50], Literature (50)[50], Methods (49)[49.7], Specialist (44)[50.5], Chemistry (41)[45]
ENTER: 99.95

Synesthetic

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Re: Suggested Solutions [Pending]
« Reply #10 on: November 11, 2008, 06:22:33 pm »
dude do u remember the question for 4c??
I just posted it, 6 months and 500 foxes.
2007- History Revs (44)[46], Chinese SL (32)[44]
2008- English (50)[50], Literature (50)[50], Methods (49)[49.7], Specialist (44)[50.5], Chemistry (41)[45]
ENTER: 99.95

nrisme

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Re: Suggested Solutions [Pending]
« Reply #11 on: November 11, 2008, 06:23:39 pm »
thats  the answer

Synesthetic

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Re: Suggested Solutions [Pending]
« Reply #12 on: November 11, 2008, 06:26:33 pm »
Many people were asking about question 3, the train one. So coblin and I took it upon ourselves to come with fully worked out solutions. Enjoy.
[images]

Damn, the latter part of these answers is completely at odds with mine ;D
2007- History Revs (44)[46], Chinese SL (32)[44]
2008- English (50)[50], Literature (50)[50], Methods (49)[49.7], Specialist (44)[50.5], Chemistry (41)[45]
ENTER: 99.95

xers

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Re: Suggested Solutions [Pending]
« Reply #13 on: November 11, 2008, 06:27:36 pm »
Many people were asking about question 3, the train one. So coblin and I took it upon ourselves to come with fully worked out solutions. Enjoy.


I got the time as 3pi seconds too, but many people said its 6pi. And the speed, i dont think its 0.

Synesthetic

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Re: Suggested Solutions [Pending]
« Reply #14 on: November 11, 2008, 06:31:07 pm »
Many people were asking about question 3, the train one. So coblin and I took it upon ourselves to come with fully worked out solutions. Enjoy.


I got the time as 3pi seconds too, but many people said its 6pi. And the speed, i dont think its 0.

Yeah I was going to say that I was skeptical about speed=0, perhaps a factor strengthening the t=6pi argument.
2007- History Revs (44)[46], Chinese SL (32)[44]
2008- English (50)[50], Literature (50)[50], Methods (49)[49.7], Specialist (44)[50.5], Chemistry (41)[45]
ENTER: 99.95