General Thoughts - Mathematics (1 Viewer)

[mc88]

Did any do the growth and decay question like me?

I did them as simultaneous equations, getting A as the subject of one, puttind that into the other equation then substituting the values in, solved that for k, then went back to the original equation, subbed in values again, as well as k and solved it for A.

I ended up ln(13/8) or something for k, and some massive number for A, which was probably because I did the question using the millions, rather than using just the numbers they gave and writing millions after it.

 

[mc88]

Did any do the growth and decay question like me?

I did them as simultaneous equations, getting A as the subject of one, puttind that into the other equation then substituting the values in, solved that for k, then went back to the original equation, subbed in values again, as well as k and solved it for A.

I ended up ln(13/8) or something for k, and some massive number for A, which was probably because I did the question using the millions, rather than using just the numbers they gave and writing millions after it.

 

[Buiboi]

hmm i subbed tthe 15/4 in to the xsquared -x +4-k
and then got a x^2 - x +0.25 and solved it like a quadratic

geez whydidnt i just sub k in to the line...i didnt notice

OMGG I JUST REALISED I PLUS'd intsead of minus!! OMG no wander i got a root in my answer ...oh fucking hell, couldnt solve afreakin QUADRATIC!!

 

[tom~sparky28]

I thought it was fairly reasonable - a bit longer than some past papers (maybe it just felt that way in exam conditions), but overall quite as expected. Hopefully 115+

lol about the October/November debate. As has been said previously, 10.6 months from the start of january definitely means november, as it means 10 whole months have already been completed, and we're part way into the 11th.

 

[Forbidden.]

yeah i got 15/4

i think my p coordinate was like (1-root2)/2...?

I got my coordinates after subbing in the k into y = k + 2 and didn't get a square root of any kind.

Question 5b) (iv) was ln 2
Question 7a) (iii) k was 15/4
Question 7a) (iv) P (1/2, 4.25) ??
Question 7b) (ii) total shaded region was 4 units sq
Question 8a) (ii) November 2010
Question 8b) (iv) p=12 q=18
Question 9b) (i) 39/51
Question 9b) (ii) (39*26*13)/(51*50*49)
Question 10a) (iii) object returns at t=7.2 seconds

I think they are good.. only lost the four marks for Q10b)(ii) so hopefully no silly mistakes.

Overall - quite easy really

Ah someone's P coordinates look more like mine ...

The test was full of stupid little tricks like "November" and the "18th birthday" shit.,

Indeed.

hey but for 5b) didnt you sovle for the constant value??
liek i think i had ln(32) at first

integrate 2t/(16 + t^2) yeah?
=ln(16 +t^2) + c
x=0, t=0
c= - ln(16)
x= ln(16 + t^2) - ln (16)
at t=4
x= ln (32) - ln (16) = ln (2)

Yep I got something very much like that .

 

[nina2sweet]

DEATH TO BOARD OF STUDIES.

that exam was bullshit.

 

[joey...]

damn i put July 2010...

what did ppl get for 10a last 2 parts?

 

[Poad]

Bleh. It was.. okaaaaay. Could've been a lot easier, though. I screwed up all of Q10. The stuff in part (a) is by far my worst topic, and the last past of (a).. sketching the displacement... Ugh. And, how were you meant to get an exact answer (like 7.2) for when it returns to the origin? I said t = 8, because thats approximately when the area above the x-axis equals the area below it. Part (b) was just 'wtf' =|

I suck at probability too, so Im pretty sure I got the Q9 bit wrong, and the one about investing money, too. I was aiming to beat my trial mark of 89% (which I was pretty disappointed in... my lowest maths assessment for the whole year) but unfortunately I dont think thats gonna happen.

Oh well.. Ext 2 Maths 2008 here I come!

(Oh, and I got September 2010. Boo)

 

[karljl]

Did any do the growth and decay question like me?

I did them as simultaneous equations, getting A as the subject of one, puttind that into the other equation then substituting the values in, solved that for k, then went back to the original equation, subbed in values again, as well as k and solved it for A.

I ended up ln(13/8) or something for k, and some massive number for A, which was probably because I did the question using the millions, rather than using just the numbers they gave and writing millions after it.

hey mc88,

in mobile fone growth...
A = 948.62 (2dp)
k = 0.49 (2dp)

 

[chocolate_lover]

It wasn't as bad as I thought it would be.

Of course there were some dodgy questions, but there were also ones that I recognised.

 

[coretez]

ohhh i got the same k value as karl but got like 15.81 for A lol...
i literally spent so long on this question cause i couldnt do question 10 anyway and still didnt get it.. how very sad
i rkn test was harder than previous years.. some odd questions

 

[joshuaali]

Bleh. It was.. okaaaaay. Could've been a lot easier, though. I screwed up all of Q10. The stuff in part (a) is by far my worst topic, and the last past of (a).. sketching the displacement... Ugh. And, how were you meant to get an exact answer (like 7.2) for when it returns to the origin? I said t = 8, because thats approximately when the area above the x-axis equals the area below it. Part (b) was just 'wtf' =|

I suck at probability too, so Im pretty sure I got the Q9 bit wrong, and the one about investing money, too. I was aiming to beat my trial mark of 89% (which I was pretty disappointed in... my lowest maths assessment for the whole year) but unfortunately I dont think thats gonna happen.

Oh well.. Ext 2 Maths 2008 here I come!

(Oh, and I got September 2010. Boo)

Accelerated, eh?

You obtain 7.2 from equating the area you found in (i) with -5t (since the velocity is a constant -5 units/s after t=6). You'll get 1.2s (which means 1.2 seconds after t=6). You add 'em up to get your final time.

PS: This question looked familiar (ref: 2005 HSC Mathematics Q 7 (b) (ii)).

 

[karljl]

And, how were you meant to get an exact answer (like 7.2) for when it returns to the origin? I said t = 8, because thats approximately when the area above the x-axis equals the area below it.

t=7.2 because distance of +ve velocity = 8.5 units
therefore with -ve velocity, u have area of triange = 2.5 units then 6 units at 5units / second

does anybody else agree with that??

 

[coretez]

hey mc88,

in mobile fone growth...
A = 948.62 (2dp)
k = 0.49 (2dp)

ohhh i got the same k value as karl but got like 15.81 for A lol...
i literally spent so long on this question cause i couldnt do question 10 anyway and still didnt get it.. how very sad
i rkn test was harder than previous years.. some odd questions

 

[mc88]

in mobile fone growth...
A = 948.62 (2dp)
k = 0.49 (2dp)

As in 948.62 million? If so, it sort of sounds like what I had.

Did you use the 1600 and just put million after it, or did you use 1600000000?

 

[starrysky]

It wasn't as bad as I thought it would be.

Of course there were some dodgy questions, but there were also ones that I recognised.

Same here. Thank God I stayed up all night and did past papers ...

I attempted every question, but lost a fair bit of marks due to idiocy/actualheaddesking/notcaring, even though I only have ten units. Shit.

It wasn't as bad as I thought it would be - I built it up so that I'd think even Question 2 onwards would challenge me, so I got through to Question 6 without too many problems (apart from Question 4 C - :mad1: I fucked it up big-time) ... then it all went downhill.

Expecting no more than 70/120 for that exam.

 

[karljl]

just the 1600

 

[cccclaire]

I thought it was a good test.

The only thing I couldn't do was the locus one, with the last part, I kept getting the gradient of sp = -1 which wouldn't make it parallel to the directix at all, but it was only worth 1 mark so I didn't bother too much.
Also I realised just as the examiner said pens down that I stuffed up one of the probability questions =/

Also I put t=7 for 10a, because as far as I'm concerned 7.2 isn't an estimate and it said "estimate".

10b was suprisingly easy, though I'm not certain I got the right answer.

 

[Poad]

@ josh and karl - Oh.. yes.. I see. Like I said, I hate that whole displacement/velocity/acceleration kind of stuff (especially involving their graphs) so that question really pissed me off.

And yeah, I did 2U Accelerated, and Ext. 2 next year. My teacher seems to think I'll own it, but im not so sure. =|

 

[transient]

hey mc88,

in mobile fone growth...
A = 948.62 (2dp)
k = 0.49 (2dp)

For A, you did have to write 948.62 MILLION right...?

Because they asked for the amount...