Maths Extension 2 Predictions/Thoughts (3 Viewers)

[lucas10champ]

so what do u think they will not mark the question altogether or try and cover up their mistake.

bro they definitely aint removing the question, i dont think theres a problem with it cause the exam gets checked many times and it would have been noticed a long time ago

 

[cheesynooby]

it doesn't seem like that big of a problem since the intended solution still works so maybe they'll just mark both solutions correct

 

[BionicMango]

Sure. But the projectile is travelling in the 4th quadrant and sin is negative. Also when you have a mass suspended from the ceiling, the left sided horizontal component is - cos because it’s in the second quadrant.

Yeah sin is negative, it’s just that I think they were assuming ‘theta’ is just a positive value and that it had to be inferred that this meant the y was negative. As in, the horizontal component is 50cos(-theta) and vertical is 50sin(-theta). I get what you mean though, they should have said -3/5.

 

[v.tex]

Literally now just gotta do textbook questions to do well in ext 2 math, unlike other years when the past papers actually counted

 

[tywebb]

mark both solutions correct

i do 3

 

[BionicMango]

i do 3

View attachment 50094

OH right because the value of A is clearly just a real number which means that any definite integral will be a constant multiple of A since that's how real numbers work (as long as all terms are made up of either constants or the dummy variable). If anything the e^(-m) term is the closest thing to a 'variable' so the integral can't be written like kA. So either most of the familiar functions' definite integrals will work or none of them will.
Method 1 is my favourite of course

 

[tywebb]

https://www.nsw.gov.au/sites/default/files/noindex/2025-10/2025-hsc-maths-extension-2.pdf is up

they didn’t edit 13a

 

[barnyard]

https://www.nsw.gov.au/sites/default/files/noindex/2025-10/2025-hsc-maths-extension-2.pdf is up

they didn’t edit 13a

bruh it's fine i doubt anyone cares about these technicalities this is actually so not a big deal
if someone answered your way they'd probably just mark it right and think ur a weirdo nerd but i dont think anyone is gonna be doing such roundabout methods when it's so easy to jst do a simple u sub instead of tryna explain to the marker that their question is poorly made. like literally who cares

 

[Trebla]

Sure. But the projectile is travelling in the 4th quadrant and sin is negative. Also when you have a mass suspended from the ceiling, the left sided horizontal component is - cos because it’s in the second quadrant.

I think the intention is that theta is just an acute angle to the horizontal and then you’re meant to infer the negative sign to the y-component due to vector direction. Similar to how when you resolve forces you don’t think about whether theta is positive or negative relative to the horizontal, instead you infer the negative sign from the vector direction.

That’s how it is usually taught and is more intuitive, rather than inferring the signs by working out a “relative” theta to the x-y plane.

 

[tywebb]

15aiii was a or otherwise question. here be a or otherwise method

 

[BionicMango]

I think the intention is that theta is just an acute angle to the horizontal and then you’re meant to infer the negative sign to the y-component due to vector direction. Similar to how when you resolve forces you don’t think about whether theta is positive or negative relative to the horizontal, instead you infer the negative sign from the vector direction.

That’s how it is usually taught and is more intuitive, rather than inferring the signs by working out a “relative” theta to the x-y plane.

Ironically, I find a negative theta more intuitive lol, or at least a negative sine

 

[tywebb]

here is a alternative sol to 16a, pretty much the same method, but gives more general result

 

[C_master]

here is a alternative sol to 16a, pretty much the same method, but gives more general result

View attachment 50286

I already completely forgot about this exam or what questions were in it
Maths is probably my strongest subject but good riddance 4u

 

[coolcat6778]

I already completely forgot about this exam or what questions were in it
Maths is probably my strongest subject but good riddance 4u

math is everyones strongest in terms of scaled mark. all the other subjects scale like dog shit

 

[tywebb]

16ciii said or otherwise

here is or othewise method

 

[BionicMango]

Cross products would make multiple questions much easier but it’s not in the syllabus so I’d imagine that wouldn’t be allowed.
Like question 13b for mx2

 

[tywebb]

Cross products would make multiple questions much easier but it’s not in the syllabus so I’d imagine that wouldn’t be allowed.
Like question 13b for mx2

this question came up in the 2023 ext 1 exam, they had some vectors and asked for area of triangle spanned by the vectors.

not everyone in nsw have been in schools in nsw for 13 years. some come from overseas already well versed in linear algebra, cross products, scalar triple products, determinants, matrices etc.

for this question it comes naturally to them as half the magnitude of the cross product of the vectors, much neater solution

so in the nesa presentation for hsc marking they said the question said "or otherwise" and so would accept oos method, incuding cross product.

 

[tywebb]

now the text-selectable version of ext 1 is on official website i have procured the following list

instances of or otherwise questions in 2025 hsc exams

std 1 and 2: none
adv: Q29a
ext 1: Q 12eii, Q13eii
ext 2 Q13cii, Q15aii, Q15ciii, Q16a, Q16ciii

haven't done em all as or otherwises

but u know where all this or otherwise stuff started?

the 1917 lc exam



so it's a VERY old thing
more to the point, who started it?
this guy



horatio carslaw - of maths building at syd uni fame

 

[tywebb]

here is or otherwise methods for the 13b, 15a using cross product

 

[tywebb]

and now i do the 1917 or otherwise question.