Maths Extension 2 Thoughts and Feelings (1 Viewer)

[yanujw]

Bro the mfs in NESA be trolling

Legit Q11 was like 2020 level quality

I wasn't too surprised, they have to make Q11 accessible for everyone and it wasn't super blatantly easy. But haha the inequalities were a joke - the blatant inequality in 12a that year 10 students can do, and the application of inequalities in 16c were pretty straightforward and helped me to not get a 0 in that question lol.

 

[ExtremelyBoredUser]

If want to estimate your aligned + moderated mark from your estimated raw here's the graphs from the last two exams. Data taken from the rawmarks database.
View attachment 36688

Pre sure scalings gonna be generous considering how the exam threw most people off

 

[ExtremelyBoredUser]

I wasn't too surprised, they have to make Q11 accessible for everyone and it wasn't super blatantly easy. But haha the inequalities were a joke - the blatant inequality in 12a that year 10 students can do, and the application of inequalities in 16c were pretty straightforward and helped me to not get a 0 in that question lol.

That moment when inequalities is the easiest question in q16

 

[idkkdi]

q16d was a neat q.
You need to recognise that it was somewhat a polynomial question.

u get |z1| = |z2| = |z3| = 1.
z1+z2+z3 = 1, z1z2z3 = 1.
1/(z2z3) + 1/(z1z3) + 1/(z1z2) = 1.
=> z2z3 + z1z3 + z1z2 = 1 (noticing mod = 1, 1/z = z_conj, and then noticing rhs is real)
Notice that you get sum, product, sum of two roots formulas. Then you can make a cubic polynomial and solve that for the three complex numbers.

if this is not the correct method, well oops lol

 

[yanujw]

=> z2z3 + z1z3 + z1z2 = 1 (noticing mod = 1, 1/z = z_conj, and then noticing rhs is real)

I'm not convinced this works. If you assume this is true and divide by z1z2z3 for example, you get 1/z1 + 1/z2 + 1/z3 = 1/z1z2z3. RHS has a modulus of 1 while the LHS has 3 terms of modulus 1. Although, maybe that is a hint in solving the equation, so feel free to correct me if I'm wrong.

 

[idkkdi]

I'm not convinced this works. If you assume this is true and divide by z1z2z3 for example, you get 1/z1 + 1/z2 + 1/z3 = 1/z1z2z3. RHS has a modulus of 1 while the LHS has 3 terms of modulus 1. Although, maybe that is a hint in solving the equation, so feel free to correct me if I'm wrong.

that's the same as saying z1 + z2 + z3 =/ 1 since lhs has mod 3 lol. ur missing that mod includes imaginary parts

i.e. |1/z1 + 1/z2 + 1/z3| =/ |1/z1| + |1/z2| + |1/z3|

 

[idkkdi]

Don't remember NSB papers since i did them long back but I would say comparatively HSC was more harder since its not as memorable

MC is def harder than ruse trials imo idk wtf some questions like theres this one question about Set 1 and Set 2 and they represent something like S1 is a dot product between some vectors and Set 2 is that 2 vectors were equal magnitude to some arbritary point N and then they somehow intersect and we had to find the radius??? bruh wtf ?? There was stupid shit like that. But half of MC was fine.

I found ruse q16 way more easier than this q16. it was really abstract and it was like go do whatever heres the question than like some hints.

If you want a gist of it:

MC, Q16 were really hard relative to most trial papers
Q11 was legit 2021 level
Q12-13was on the level of those trials and maybe slightly easier?
Q14-15 was harder than most trial Q15s and designed to reduce time for Q16. Its purposely distracting with content overload (legit 1 fucking page for a mechanics question bruh wtf) so yea it was contributing to Q16s difficulty, but it wasnt too bad lol

q9. s1 was a sphere. s2 was a plane. they intersect to form a circle. and then u do some simple trig to get the answer. but ye, definitely some imagination involved there.

 

[jamal123999]

yo what was the answer for 16b, for initial velocity, was it 39.1ms^-1?

 

[Jordi El Nino Polla]

Brutal by the reactions here. When I did my HSC in 2021 I thought that paper was way harder than 2020, didn't expect 2022 to be even worse.

 

[dansk1er]

Lowkey pretty upset with this exam, Did the 2020 and 2021 exams timed and easily cleared e4 aligned, this year I am hoping for low 60s raw. NESA better make align marks significantly better to make up for just how much harder this test really was. Oh well, hopefully I can make up for it with 3u on monday.

 

[MemeCognoscente]

Lowkey pretty upset with this exam, Did the 2020 and 2021 exams timed and easily cleared e4 aligned, this year I am hoping for low 60s raw. NESA better make align marks significantly better to make up for just how much harder this test really was. Oh well, hopefully I can make up for it with 3u on monday.

amen brother

 

[tywebb]

Here is the solution by Lkc36 who has beaten Terry Lee to it

 

[tywebb]

Here is another set of solutions by MOK - slightly incomplete as it did not have a serious attempt at 16b, but that is done in Lkc36's solutions who got 39.1m/s.

 

[tywebb]

yo what was the answer for 16b, for initial velocity, was it 39.1ms^-1?

Looks like Lkc36's solution concurs with your answer.

 

[tywebb]

On the other hand the solution to 16b that the Sydney Morning Herald put up last night has a different answer 33.6 m/s but I reckon she is wrong.

https://www.smh.com.au/politics/nsw...-exam-question-explained-20221020-p5brm4.html

To save you the agony of watching the video here is a screenshot of the working.

She seems to assume the final velocity is the same as the initial velocity - not an appropriate assumption in a resistive motion question.

 

[okkk]

On the other hand the solution to 16b that the Sydney Morning Herald put up last night has a different answer 33.6 m/s but I reckon she is wrong.

https://www.smh.com.au/politics/nsw...-exam-question-explained-20221020-p5brm4.html

To save you the agony of watching the video here is a screenshot of the working.

She seems to assume the final velocity is the same as the initial velocity - not an appropriate assumption in a resistive motion question.

View attachment 36698

Yeah surely that's wrong, the person assumed that the impact speed of impact to the ground is the same as the initial velocity unless I'm missing something normally it's different

 

[tywebb]

Yeah. It is going to be interesting to see what matrix eduction, Terry Lee and itute do now. Let's hope they don't just copy the Sydney Morning Herald's answer.

 

[notme123]

Yeah surely that's wrong, the person assumed that the impact speed of impact to the ground is the same as the initial velocity unless I'm missing something normally it's different

the assumption is completely wrong lol. violates conservation of energy

But overall, I think this test was good actually. Time would've been your worst enemy. There was less room for silly mistakes compared to last year since this year there were way more 'show' questions. q16 this year i reckon was more challenging than last year but the rest of the test was on the same level. Especially that last sum and product of roots q. if you hadn't seen that q before, you would've been stumped (like I was). 16(a) and (c) were fine tho. 16(b) on the other hand felt illegal lol. Would never think of integrating 0 -> 0, especially when air resistance changes direction during flight.

 

[kzbenn]

(teacher) very difficult paper, harder than sample, 2020, 2021. q11,12,13 good q14,15,16 ridiculous. mult choice also horrible. I reckon I only got 80 in the time frame. Advice - nothing you can do now, everyone is in the same situation. put it from your minds and prep for ext1. and also, this stupid exam doesn't define you.

 

[notme123]

Actually 1 question id like to comment on is 14 a) i. This is about linear independence which is an algebra concept that comes up in uni. From what I recall, I was not taught this in high school. Sure you could figure it out by saying they're not parallel but throwing students straight into a proof like that is whack.