Post by: Joseph41 on October 26, 2020, 09:01:37 am
When the exam has finished, use this thread to chat all things Maths Advanced.
Post by: Tierney_P on October 26, 2020, 03:04:48 pm
Post by: keltingmeith on October 26, 2020, 04:06:19 pm
WHO HATED THE CRICKET QUESTION?!?!?! i was absolutely stumped :P
My God I wish I could downvote this, that was terrible 😂
Post by: RuiAce on October 26, 2020, 04:16:12 pm
(I'm assuming stumped was a pun lmao)
Post by: fun_jirachi on October 26, 2020, 04:34:29 pm
My God I wish I could downvote this, that was terrible 😂
I was absolutely knocked over with pace, real pace by that joke
Post by: Tierney_P on October 26, 2020, 04:47:57 pm
What was the question? I haven't seen any of the paper yet
(I'm assuming stumped was a pun lmao)
haha ;) cricket insect
nah it was about a scientist measuring the relationship between temperature and amount of cricket chirps...gave us a box plot of temperatures over 20 days and told us there were 684 cricket chirps in total; gave mean temperature...
and then the least squares regression line with
blah di blah (a lot of information my poor brain!)
then we had to figure out amount of chirps expected on a 19C day :P i was like um yeh well NOPE
Post by: RuiAce on October 26, 2020, 04:50:03 pm
Post by: rirerire on October 26, 2020, 05:02:48 pm
Post by: rirerire on October 26, 2020, 05:05:06 pm
haha ;) cricket insectwow good memory how did you remember that?? the answer was 29 that's all I know ahahah wish I knew that in the exam though
nah it was about a scientist measuring the relationship between temperature and amount of cricket chirps...gave us a box plot of temperatures over 20 days and told us there were 684 cricket chirps in total; gave mean temperature...
and then the least squares regression line with(where y=chirps and x=temp)
blah di blah (a lot of information my poor brain!)
then we had to figure out amount of chirps expected on a 19C day :P i was like um yeh well NOPE
Post by: Tierney_P on October 26, 2020, 05:05:25 pm
how tf were we supposed to answer that cricket question though...and apparently standard had the same one?? ugh I'm so mad at my school for never teaching us a thing about regression lines, everyone in my year was absolutely stumped with that question and I'm mad at myself for not doing enough past papers lol
aww dammit! i knew regression lines but i was like :o INFORMATION OVERLOAD :o and not sure how to apply it in that situation! weird question...far out
edit: yep i could have done with knowing the answer in the exam lols
Post by: sroe on October 26, 2020, 05:15:43 pm
...and apparently standard had the same one??
I heard there was a 23 mark cross over with the standard paper. It would be interesting to know which questions.
Post by: rirerire on October 26, 2020, 05:45:00 pm
I heard there was a 23 mark cross over with the standard paper. It would be interesting to know which questions.yeah I heard something similar. I think it must've been the crickets one, the annuities one and the venn diagrams/probability questions. haven't done a venn diagram since like year 10 so had a mini heart attack when I saw that one lol
Post by: sroe on October 26, 2020, 05:54:57 pm
yeah I heard something similar. I think it must've been the crickets one, the annuities one and the venn diagrams/probability questions. haven't done a venn diagram since like year 10 so had a mini heart attack when I saw that one lol
Good call. Maybe the normal distribution one too?
Post by: sroe on October 26, 2020, 05:56:00 pm
Post by: BakerDad12 on October 26, 2020, 06:24:21 pm
Post by: hooter03 on October 26, 2020, 06:58:19 pm
I heard there was a 23 mark cross over with the standard paper. It would be interesting to know which questions.
I know this is the advanced forum, but I thought I'd comment on what the standard paper had and you can check the cross over: the crickets, Wilma (i think that's her name) and the annuities table, the decagon, the Z score question with Simon and his IQ... these were the difficult ones but I think there might be a couple more not entirely sure.
Post by: RuiAce on October 26, 2020, 10:51:02 pm
Tank
(https://i.imgur.com/LOabH75.png)
Camping
(https://i.imgur.com/ln3wNdh.png)
Decagon
(https://i.imgur.com/3WiwBLf.png)
Tina's Withdrawals
(https://i.imgur.com/MaD9UoA.png)
Crickets chirping
(https://i.imgur.com/pTgnZfi.png)
Post by: RuiAce on October 27, 2020, 01:37:42 am
Clicking an image can make it automatically resize into a more readable view.
Multiple Choice
Questions 1-10
(https://i.imgur.com/FgiI8mO.png)
Short Answer
Questions 11-14
(https://i.imgur.com/R46p8pa.png)
Questions 15-18
(https://i.imgur.com/QwSMZgu.png)
Questions 19-21
(https://i.imgur.com/karlr5O.png)
Questions 22-25
(https://i.imgur.com/wDPhZeK.png)
Questions 26-28
(https://i.imgur.com/GsDoYVT.png)
Questions 29-31
(https://i.imgur.com/mRnk2DB.png)
Post by: sroe on October 27, 2020, 07:54:53 am
Some late night solutions to the whole paper.
These are awesome, thank you!!
Just with Q27 (the crickets one) you've written =29.036... --> Hence 21 chirps...
Should it not also be 29?
Post by: BakerDad12 on October 27, 2020, 08:16:05 am
Post by: RuiAce on October 27, 2020, 10:02:54 am
These are awesome, thank you!!Oh dear haha.
Just with Q27 (the crickets one) you've written =29.036... --> Hence 21 chirps...
Should it not also be 29?
Context: I screwed up the question a little in my first attempt. Found the mistake, and managed to get the correct 29.036. But then forgot to fix the conclusion! I'll make sure to fix that.
Post by: Natasack on October 27, 2020, 10:28:17 am
I thought 8 and 10 were very hard, I was basically making an educated guess on both of them.what was the answer for 10 multiple choice?
Post by: RuiAce on October 27, 2020, 10:36:20 am
what was the answer for 10 multiple choice?I will get to that.
Post by: rirerire on October 27, 2020, 02:07:32 pm
made sooooo many dumb errors I genuinely don't know if i even passed this paper. ugh I feel like i've completely jeopardised my atar with this one stupid exam
Post by: RuiAce on October 27, 2020, 04:39:36 pm
reading these answers feels bad manIf they were silly mistakes I imagine you'd still get a reasonable amount of partial marks for your attempts. They shouldn't punish you that heavily if you showed reasonable understanding, even if there were errors along the way.
made sooooo many dumb errors I genuinely don't know if i even passed this paper. ugh I feel like i've completely jeopardised my atar with this one stupid exam
Post by: BakerDad12 on October 27, 2020, 06:48:16 pm
Post by: RuiAce on October 28, 2020, 03:02:42 pm
Post by: roy g biv on October 30, 2020, 10:56:45 pm
h(x) = f(g(x))
Examining around x = 3:
h(x) = f(g(2.9))
h(x) = ~ f(0.1)
h(x) = ~ 1.81
h(x) = f(g(3))
h(x) = ~ f(0)
h(x) = ~ 1.8
h(x) = f(g(3.1))
h(x) = ~ f(0.1)
h(x) = ~ 1.81
Clearly, there is a minimum point :-)
Therefore answer is D, not C. Other two max stationary points occur when ~f(0.8). i.e. we need g(x) to be 0.8 in order to get f(g(x)) to become f(0.8).
g(x) = 0.8 at 2 places. Therefore two stat points.
If you're still not convinced, try using desmos to experiment:
g(x) = 0.5(x-3)^2
f(x) = 2e^-(0.7x-0.5)^2
h(x) = f(g(x))
Post by: RuiAce on October 30, 2020, 11:05:30 pm
Q10. Should be D, i think.The stationary point at \(x=3\) was already located. There is nothing to convince me of here.
h(x) = f(g(x))
Examining around x = 3:
h(x) = f(g(2.9))
h(x) = ~ f(0.1)
h(x) = ~ 1.81
h(x) = f(g(3))
h(x) = ~ f(0)
h(x) = ~ 1.8
h(x) = f(g(3.1))
h(x) = ~ f(0.1)
h(x) = ~ 1.81
Clearly, there is a minimum point :-)
Therefore answer is D, not C. Other two max stationary points occur when ~f(0.8). i.e. we need g(x) to be 0.8 in order to get f(g(x)) to become f(0.8).
g(x) = 0.8 at 2 places. Therefore two stat points.
If you're still not convinced, try using desmos to experiment:
g(x) = 0.5(x-3)^2
f(x) = 2e^-(0.7x-0.5)^2
h(x) = f(g(x))
The mistake was that for the second part of the solution, I somehow borrowed the stationary point to \(y=g(x)\) instead of \(y=f(x)\). I do not need Desmos to convince me of that mistake.
(Mistake will be fixed soon)
Post by: roy g biv on October 31, 2020, 09:48:41 am
To be honest, I saw that C had been put as the answer, and without reading your solution, I assumed you were missing the stat. pt. at x=3 similar to how many other students missed it.
My bad! Shouldn't have assumed :)