General Thoughts: Mathematics Extension 2 (1 Viewer)

[bendertherobot]

Re: What did you think?

THat test was AWESOME!!!!...I totally blitzed it, easily 110+






nah...seriously it was an epic fail LOL

 

[mick135]

Re: What did you think?

anyone know wtf the integral of
tan(inverse)x was?
if it was meant to be simple, well it wasnt ok?!

 

[18836165]

Re: What did you think?

agreed
yr 12 - 2008...
we may be really really cool - but the bastards set the hardest ext 2 paper in a long while haha

there were so many things missing which sucked
where was the simple conics question just asking
"draw this stating the asymptotes/directicies, foci and x-intercepts"?
the conics questions they gave were harsh

i did the probabilities

it looked something like this for memory
3 balls same:
(n/3n) x (n-1)/(3n-1) x (n-2)/(3n-2)

3 different:
(n/3n) x (n/3n-1) x (n/3n-2)

the last bit i didnt get and made up - which inturn affected the bit after that
(if i'm wrong... i dont care , but i'm pretty sure thats right)

i'm gonna buy next yrs "past hsc papers" cause it has to acknowledge the ppl who made it - then i will hunt them down and make them pay - WHO's WITH ME?! haha

I did that too, hope it's right.

Yeah the test was pretty bad overall. Even some of the integrations took ages.

 

[18836165]

Re: What did you think?

anyone know wtf the integral of
tan(inverse)x was?
if it was meant to be simple, well it wasnt ok?!

Use Intergration By Parts.

Make u = arctanx

u' = 1 / (1+x^2)

v' = 1

v = x

Then just go uv - Int[vu']

The int. becomes a log.

 

[karar]

Re: What did you think?

hey guys see the last quesiton for quesiton 1 wtf..

com'on bos wtf 4 marks to do 3 sperate intergals..

now u tell me ??

 

[Nivi7]

Re: What did you think?

Use Intergration By Parts.

Make u = arctanx

u' = 1 / (1+x^2)

v' = 1

v = x

Then just go uv - Int[vu']

The int. becomes a log.

yay!!! now I get at least 3 marks!!!

btw, to da person on bos who went around telling ppl that this would be the hardest paper eva...thanx for jinxing the exam

 

[cccclaire]

Re: What did you think?

i hated the 2 4-mark intergration questions. I didn't get them at first, then went back at the end and got them


How did you do

1/x(2x-1)^1/2 though?

 

[I-Love-Jesus]

Re: What did you think?

Yeah...? I'd like to know that too!^^

 

[karar]

Re: What did you think?

i hated the 2 4-mark intergration questions. I didn't get them at first, then went back at the end and got them


How did you do

1/x(2x-1)^1/2 though?

use sub u^2=2x-1

and then play around with u and u^2 and dont forget to make x the subject

 

[f(x)=x^2]

Re: What did you think?

i dont know... some ppl are saying it's hard, some say they finish with 45-30 mins left.... can ppl tell which school they come from so we know what to expect for a more meaningful comparision of hardness/easiness, i reckon is kinda ok... except i lost 3 marks over 62 omega=cis2pi/3 arrrrrrr !

 

[cccclaire]

Re: What did you think?

use sub u^2=2x-1

and then play around with u and u^2 and dont forget to make x the subject

I might have subbed in let x=sec^2x /2

It sort of worked I think. i got an answer of pie/12.

Is that completely wrong?

 

[18836165]

Re: What did you think?

i hated the 2 4-mark intergration questions. I didn't get them at first, then went back at the end and got them


How did you do

1/x(2x-1)^1/2 though?

Let u = Sqrt[2x-1]
U^2 = 2x -1
u du = dx

Therefore the int. becomes

Int [ u du / { (u^2 - 1)/2 X u}

Anyway you get Int [ 2/ (u^2 + 1) ]

then just Int it like a arctan.

 

[friction]

Re: What did you think?

i tihnk i did the probability question and i got stuff in the ratio of (forget the exact numbers ) but it was in the form of ninths.. like 1/9:2/9:4/9 .. ?? anyone else get something like that?

I got 1:4:2 i think

Or 1:2:4

 

[pshim90]

Re: What did you think?

gaahhh...
hoping i can get mid E3,, if thats any good...

 

[midifile]

Re: What did you think?

I got 1:4:2 i think

Or 1:2:4

I think I got 1:2:6

=S

 

[Kearnzo]

Re: What did you think?

I might have subbed in let x=sec^2x /2

It sort of worked I think. i got an answer of pie/12.

Is that completely wrong?

No, that is what I did and you get exactly the same answer as using u^2 = 2x-1.

Though your answer is wrong, should be pi/6 I think. Though you should still get full marks, just dropped a two somewhere.

 

[ngogiathuan]

Re: What did you think?

i hated the 2 4-mark intergration questions. I didn't get them at first, then went back at the end and got them


How did you do

1/x(2x-1)^1/2 though?

I put 2x-1 = u, then get sth like 1 / (u+1) u^1/2
Then let u^1/2 = v again () so u = v^2
sub in and integrate it becomes arctan v

i got pi/6 as well cheers

 

[k--man2]

Re: What did you think?

I might have subbed in let x=sec^2x /2

It sort of worked I think. i got an answer of pie/12.

Is that completely wrong?

i dont think u had to do any of that
i jus split the fraction up
so i got 1/x + 1/(2x-1)^1/2

and then the first one becomes a log and the second one jus becomes a simple linear integration

 

[bendha]

Re: What did you think?

Q6 and 8 were hard as. Btw does anyone know what "the physical significance of b" really was?

terminal velocity?

 

[cccclaire]

Re: What did you think?

No, that is what I did and you get exactly the same answer as using u^2 = 2x-1.

Though your answer is wrong, should be pi/6 I think. Though you should still get full marks, just dropped a two somewhere.

actually I might have got pi/6, I forget.

Even if I did write pi/12 I'd still get 3/4, so I'm happy now =] =] =]