Maths Extension 2 Predictions/Thoughts (3 Viewers)

[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.

 

[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

 

[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

 

[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]

and now i do the 1917 or otherwise question.

 

[tywebb]

well it only took 108 years for that to happen.

better late than never

 

[nonya2000]

Every other state learns the cross product specialist maths

 

[Luca26]

Every other state learns the cross product specialist maths

4 unit used to have it, I think - the 1970s version when 4 unit was 2 years

 

[tywebb]

i wanna know when nesa doing presentation for hsc marking.

usually it is last saturday in february of following year, and in recent years it is 9am, guthrie theatre at UTS.

ain't it sus that there were 3 questions saying or otherwise - all 3 of which are cross product?

they obviously knew that or otherwise meant cross product.

so why put or otherwise if they don't want cross product

3 TIMES FOR GOODNESS SAKE!

fair enough once in a blue moon like 1 question in 2023 ext 1

but 3 in same exam?

that's very contrived i think.

 

[tywebb]

i’m gonna rename the 2025 mathematics extension 2 hsc exam

the 2025 cross product exam

 

[BionicMango]

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.

I remember that question, I was thinking that half the cross product is the most elegant and easy solution as well. Or at least using the determinant of a 2x2 matrix with the entries being the two vectors (which essentially is the cross product).
To answer that question I considered the rectangle and subtracted triangles, as that’s how I first learnt that the determinant of a 2x2 matrix represents the area of the unit square after being transformed. Thanks Khan Academy

 

[coolcat6778]

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.

I don't get why they don't just add cross product in the syllabus. Every other state covers it, and brits do as well.

It's not going to dilute the stupid question 16s (which I can't do anyway) all it does is give us more options to solve a question

 

[coolcat6778]

bro what is the big deal of question 7 question? it's just a sketching question lol


I did all these questions without the use of calculations lol

 

[coolcat6778]

Process of elimination is a very good skill to develop for HSC mcq of any subject. You WILL thank me later.

Anecdotal evidence:

In '24 HSC Physics, my mcq mark was 12/20 before I developed "systematic guessing skills" In '24 HSC MADV, my mcq mark was 7/10 before I developed "systematic guessing skills" In '25 HSC Chem, my mcq mark was 16/20 and I literally guessed half of the questions lol In '25 HSC MX2, my mcq mark was 8/10 and I literally guessed some

"Teach me your ways, how do I systematically guess?"
You just choose the most logical answer. Instead of doing A B C D and guessing B for no reason, think about why? Is it the odd one out?

Is it the odd one out?
This is the question you need ask yourself every time you're stuck on an apparently impossible question. This is your next best chance of scoring it right. Deductive reasoning doesn't even have to involve pens down, it can also just involve pattern recognition like the following two examples.

Example 1
Just look at this question (don't worry you don't require chem knowledge to answer it like I did)
Bla bla bla, get to the fucking point. Don't bother reading a single line. Go straight to the options.

Notice how straight off the bat, B is the odd one out; followed by C; finally followed by Z? This gives D as the final answer
(which was correct)

Example 2
Bla bla bla keep fucking yapping. (I didn't read a single word of the question in the exam)

A a rectangle is a parallelogram, which is like a square. Odd one out is a fucking rhombus (which was correct)

 

[Luca26]

Example 2
Bla bla bla keep fucking yapping. (I didn't read a single word of the question in the exam)
View attachment 50383
A a rectangle is a parallelogram, which is like a square. Odd one out is a fucking rhombus (which was correct)

Re example 2, a rectangle is a parallelogram with a 90 degree angle or equal diagonals

A rhombus is a parallelogram with equal sides or perpendicular diagonals

A square is a rhombus that is also a rectangle, or a rectangle that is also a rhombus

I don't see why rhombus is an "odd one out" option here