# Someone post up the answers :D (1 Viewer)

#### henry08

##### Active Member
Rampager said:
Question 9 b) ii) \$975.

Question 10 a) 5ln5 - 4

Question 7 a) e^(3) and e^(-1)

Question 6c) 18.75(PI) units^2

Question 6b)i) 20
ii) t = 10
iii) t = 6
iv) forget.
I got the same for 9 and 10. Can't remember the rest.

#### Rampager

##### Member
7a) x = 2e^(-3) ? Thats it? Sorry Ipod, I think you got it wrong.

ln x - (3/ln x) = 2
Let u = ln x

u - 3/u = 2
u^2 - 3 = 2u
u^2 - 2u - 3 = 0
(u - 3)(u + 1) = 0
u = 3, u = -1
ln x = 3, ln x = -1
x = e^(3) and x = e(-1)

#### ipod21

##### Member
q7)c)
i got ii) 7/27
iii) 4/9

q9)a) i)0.0225
ii)0.17

doubt they are right though :S

#### betraya

##### ABC
Rampager, lnx =3 is the only answer, you can't have lnx=-1 because it's undefined so lnx=3 and this e^3 is the only answer

#### Rhanoct

##### zzzzz
ipod21 said:
q7)c)
i got ii) 7/27
iii) 4/9

q9)a) i)0.0225
ii)0.17

doubt they are right though :S
yep they're right

#### echeng

##### New Member
ummm i finished 1-9 within 1.5 hour~ went bak to check over and left 30 minutes for Q10~ b) was easy i finished it all! but a) kinda got me =.= i think at about 5 minutes till pens down, i figured it out tat its a inverse trig kinda question! so i wrote A=7ln5-[e^y +2y] (with the boundaries 1n5 and 0)but i did not hav time to finish the last step ! wat can i possibly get? a 3/5?

#### Bekhit

##### .
ewasemma said:
Hey guys just wondering.. what would an 86/120 be roughly as a moderated mark for maths. thanks
they say a raw mark of around 86 or 87 from 120 will scale into da 90s
so its prob a high band 5 or an early band 6

Rampager said:
Band 4, unlikely Band 5.
lol u idiot he didn say raw.

Last edited:

#### ipod21

##### Member
probabilty"

q9)a) i)0.0225
ii)0.17

I wrote a)i) =2.25%
ii)= 17%.

i had no idea why i changed them to %............. argh! there goes more marks

#### Rampager

##### Member
betraya said:
Rampager, lnx =3 is the only answer, you can't have lnx=-1 because it's undefined so lnx=3 and this e^3 is the only answer
Eh? ln x = -1 can be done...
You're thinking of ln (-1) = x which is undefined.

But ln x = -1 can be done and you can try this on your calculator, go for it.

#### ipod21

##### Member
Rampager said:
7a) x = 2e^(-3) ? Thats it? Sorry Ipod, I think you got it wrong.

ln x - (3/ln x) = 2
Let u = ln x

u - 3/u = 2
u^2 - 3 = 2u
u^2 - 2u - 3 = 0
(u - 3)(u + 1) = 0
u = 3, u = -1
ln x = 3, ln x = -1
x = e^(3) and x = e(-1)
i see what u did..looks right! but i did this... now it it looks wrong:
InX-3/InX=2
InX . InX -3 =2InX (multiply by InX to rid the fraction)
In(X+X) -2InX= 3
In (2X)- InX^2=3
In(2X/X^2)=3
In(2/x)=3
In(2/X)=3Ine
2/X=e^3
X=2/e^3

#### hollyy.

##### stop looking at me swan.
minijumbuk said:
f'(x) = k(b2x - x3/3)
f(x) = k(b2x2 - x4/12) + C

When x = b, y = 0

0 = k(b4/2 - b4/12) + C
C = - 5b4k/12

f(x) = k(b2x2 - x4/12) + - 5b4k/12

When x = 0,
f(x) = - 5b4k/12
Therefore 5b4k/12 below x-axis
holy mother of god i got it right :jaw:

#### velzee

##### In silence let him lie.
What did people get for q c ii iii ??

#### ewasemma

##### New Member
Bekhit said:
they say a raw mark of around 86 or 87 from 120 will scale into da 90s
so its prob a high band 5 or an early band 6

lol u idiot he didn say raw.
o-m-g. thankyou so much u have just restored my confidence

hehe

#### Supaman92

##### New Member
ipod21 said:
probabilty"

q9)a) i)0.0225
ii)0.17

I wrote a)i) =2.25%
ii)= 17%.

i had no idea why i changed them to %............. argh! there goes more marks
thats right though isn't it? i got 0.0225, and then i said so therefore 2.25%chance blah blah, and similarly for b??

#### iluvGG

##### Member
Bekhit said:
they say a raw mark of around 86 or 87 from 120 will scale into da 90s
so its prob a high band 5 or an early band 6
even for a test this easy?? i hope so..

#### annnieoooo

##### New Member
ipod21 said:
probabilty"

q9)a) i)0.0225
ii)0.17

I wrote a)i) =2.25%
ii)= 17%.

i had no idea why i changed them to %............. argh! there goes more marks

do you lose marks writing it as a %?

#### Rubes08

##### New Member
Why is that a mistake, can't you have a % probability. There is a 70% percent chance that someone has a mobile phone in this room

#### Bekhit

##### .
ewasemma said:
o-m-g. thankyou so much u have just restored my confidence

hehe
nwz lol...

iluvGG said:
even for a test this easy?? i hope so..
i guess it should vary from year 2 year depending on da exam and da state
so im not sure bout dis year, but i doubt it will b far off...i hope so 2 lol

##### New Member
its not 0.0225

you all forgot whats going on