Maths Extension 2 Thoughts and Feelings (2 Viewers)

[pogchampion]

how would u compare it to nsb/ruse trials? still trying to get a gauge of level here.

i thought 2021 hsc wasnt as easy as what seems to be said here lol

I think same as nsb 2021, harder than nsb or james ruse 2022

 

[idkkdi]

q16 for 2020, 2021 aren't even comparable too 2022 thats all I can say

last q of 2021 wasn't hard. it was just weirdly placed. caught like everyone off guard with the brute testing method lmao

 

[Vall]

anyone got the paper?

I got one Q

 

[yanujw]

Breakdown of Q16 for those wondering who did not do the exam.

Part (a) -> three complex numbers, which are the vertices of an equilateral triangle lie on the perimeter of a square with edges (-5,-5), (5,-5), (5,5) and (-5,5) in the Argand diagram. If one complex number is at 5 + i, find the other complex number in the counterclockwise direction.

Part (b) -> An object is released at speed vertically and has resistance mkv. Find the initial velocity if it strikes the ground again after 7 seconds.

Part (c) -> The Am-GM for n terms was given, prove that abc < (S/6)^3/2 where a, b and c are the side lengths of a prism with surface area S. Then deduce that the prism with max volume given by a constant surface area is a cube.

Part (d) -> Solve for three complex numbers with the same modulus, a sum of 1 and a product of 1.

Let me know if there are any errors in my memory.

 

[idkkdi]

I think maybe 2x as hard. It all Of the questions were pretty time pressured, but didnt require lots of genius to solve.

oh is this a bit of a 'needed to do terry lee' type paper?

I think same as nsb 2021, harder than nsb or james ruse 2022

yikes that's pretty hard lmfao

 

[yanujw]

Question 15;

Someone has posted the first part above already

Part (b) -> A piston is moving in SHM with a centre displacement of 0.15m and a minimum displacement of 0.03cm (cant remember the figure correctly). If the piston is 0.8kg, and completes 40 full motions per second, what is the maximum force that needs to be applied to sustain this motion.

Part (c) -> Integrate sin^-1(sqrt(x/(1+x^2))) using the sub x = tan^2 theta

Part (d) -> use the triangle inequality to show that if |z - (4/z)| = 2, then |z| <= 1 +sqrt(5) (again I cannot remember the numbers accurately, let me know if you have any corrections)

 

[Como90]

last page is missing for some reason (not mine)

 

[sga2]

Part (c) -> Integrate sin^-1(sqrt(x/(1+x^2))) using the sub x = tan^2 theta

was surprised to see they gave the substitution for us

 

[Vall]

Full paper now

last page is missing for some reason (not mine)

I gotchu

 

[yanujw]

if D is what i think it is. it isn't that bad.
You just to have make some WLOG statements, like u often do to simplify complex problems.

d) x1 + x2 +x3 = 1, cos(a) + cos(b) + cos(c) = 1

r^3 = 1, r = 1.
e^i(a+b+c) = cos(a+b+c) + isin(a+b+c) = 1. sin(a+b+c) = 0. a+b+c = 0.

WLOG let a = 0.
b = -c.

2 cos(b) = 0,
b = pi/2, c = -pi/2.

1,i,-i

though i might be missing something obvious here & u would probs need a bit more rigour

I had remembered it incorrectly. According to the paper you had to find ALL solutions to that triplet of conditions.

 

[aim for 95+]

was surprised to see they gave the substitution for us

Did you finished that question, I still don't have any idea with that angle

 

[idkkdi]

I had remembered it incorrectly. According to the paper you had to find ALL solutions to that triplet of conditions.

ye that makes more sense lol

 

[J Papi]

Would the scaling for our exam be better then the last few years considering it was more difficult or is that not how it works?

 

[tywebb]

last page is missing for some reason (not mine)

Page 11 is missing too.

Here it is.

 

[yanujw]

Thoughts and feelings? You should've called this thread 'thoughts and prayers'

 

[Como90]

Page 11 is missing too.

i have what should be the full paper here

 

[idkkdi]

Would the scaling for our exam be better then the last few years considering it was more difficult or is that not how it works?

yes, unless negligible factors become non-negligible. e.g. 2022 cohort just happens to have absurdly high average ability.

 

[sga2]

Did you finished that question, I still don't have any idea with that angle

 

[ExtremelyBoredUser]

Bro the mfs in NESA be trolling

Legit Q11 was like 2020 level quality

then they ramped up the difficulty. They dgaf abt going slowly in the difficulty level

View attachment 36687

Got the same thing but did it differently in that xtanxsec^2x part:

Let u = tanx so du = secxtanx du
then u get an integral
integral from 0 to 1 utan^-1(u)

Happy we got the same thing haha i didnt have much time to check back lol

 

[Vall]

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.