Maths Ext 2 Predictions/Thoughts (1 Viewer)

Siwel

Active Member
i woudlve thought the same as well.
i was like theta=0, makes sense, theta=pi/4 and thought ive done a great job now let me contemplate 16a) for an hour

tywebb

dangerman
Just finished watching the video. My only criticism is at the very end he used a because symbol whereas he should have used a therefore symbol

notme123

Well-Known Member
Just finished watching the video. My only criticism is at the very end he used a because symbol whereas he should have used a therefore symbol
unwatchable. this kid shouldn't even be doing maths let alone 4u. jk jk but thats such a simple mistake how can you screw that up thats worse than my mistake.

Siwel

Active Member
unwatchable. this kid shouldn't even be doing maths let alone 4u. jk jk but thats such a simple mistake how can you screw that up thats worse than my mistake.
yeah i would say messing up algebra is underappreciated marks wise so maybe i get 5, i did have the intent to get the right answer

notme123

Well-Known Member
yeah i would say messing up algebra is underappreciated marks wise so maybe i get 5, i did have the intent to get the right answer
exactly, might as well give me a sr at this point.

Siwel

Active Member
exactly, might as well give me a sr at this point.
ngl for the weird circle and ln function volumes i somehow made up my own way to find the volumes rotated and got the right solution

-insert title here-
Matrix solutions: https://www.matrix.edu.au/2021-hsc-maths-ext-2-exam-paper-solutions/

Other sites to keep an eye on are

and

Historically Terry Lee used to be the first with solutions up.

Recently he has been beaten by a few others.

Itute are very slow to put them up - maybe a month or so - some say they take a wiser approach than rushing to be the first.

Itute also seem to be consistently the most complete too - even putting them up for Standard 1 - which is very rare.
Matrix didn't put a dashed line for the straight line segment joining z=0 to z=-π. -1 mark.

notme123

Well-Known Member
ngl for the weird circle and ln function volumes i somehow made up my own way to find the volumes rotated and got the right solution
i didnt even realise you could do have a cube - a hemisphere i did a full integral hahaha

tywebb

dangerman
unwatchable. this kid shouldn't even be doing maths let alone 4u. jk jk but thats such a simple mistake how can you screw that up thats worse than my mistake.
My criticism stands.

But I want to downplay it. It's not a great drama.

He went through quite a bit of hefty algebra and I'm glad he was the one doing it, not me.

Overall I think he did a great job.

notme123

Well-Known Member
My criticism stands.

But I want to downplay it. It's not a great drama.

He went through quite a bit of hefty algebra and I'm glad he was the one doing it, not me.

Overall I think he did a great job.
how does one even get chosen to do this.
1. go to a prestigious school which will pay the smh to do this article
2. become ranked first in x2
3. profit

Siwel

Active Member
how does one even get chosen to do this.
1. go to a prestigious school which will pay the smh to do this article
2. become ranked first in x2
3. profit
on the facebook 2 days before they asked ppl, are you 1st in your school for x2?

notme123

Well-Known Member
on the facebook 2 days before they asked ppl, are you 1st in your school for x2?
i did not see this and i refresh facebook every 2 seconds

wait which fb page

Siwel

Active Member
i did not see this and i refresh facebook every 2 seconds

wait which fb page
the 3u and 4u one

Siwel

Active Member
whatttt i did not know those existed
they do, but honestly no one uses them

5uckerberg

Active Member
ah yes the classic article where boomers question why we still do things like this because it has no value to society. a pattern ive noticed is that top schools always get the opp to do this.
You took the words right out of my mouth.

s97127

Member

For this question, i want to prove 5^n -2^n - 3^n > 0 for n>= 2

(2+3)^n - 2^n - 3^n = 2^(n-1).3 + 2^(n-2).3^2 +....+ 3^(n-1) > 0 (QED)

Is this proof correct?

AlphaBetaThetaGamma

New Member
View attachment 33882
For this question, i want to prove 5^n -2^n - 3^n > 0 for n>= 2

(2+3)^n - 2^n - 3^n = 2^(n-1).3 + 2^(n-2).3^2 +....+ 3^(n-1) > 0 (QED)

Is this proof correct?
I'm really confused at it. Let me see if latex works.
By first glanace no. wat about < .

Trebla

View attachment 33882
For this question, i want to prove 5^n -2^n - 3^n > 0 for n>= 2

(2+3)^n - 2^n - 3^n = 2^(n-1).3 + 2^(n-2).3^2 +....+ 3^(n-1) > 0 (QED)

Is this proof correct?
Almost...except you forgot the binomial coefficients.

Also, generally speaking, proving something is positive to prove it is non-zero doesn’t always work (it works in this case though). You can have expressions that can be positive or negative but is non-zero.

Eagle Mum

Well-Known Member
Correct I got 100 for x1 but i got nowhere close to a state rank.
I imagine that by scaling extension students up, it’s quite compacted at the top, so amongst the cohort with a scaled mark of 100 would be a range of raw marks, but anyone who achieves a raw mark of 100 deserves to be equal first. Students in different schools who achieve a perfect score in the exam shouldn’t be ranked based on school assessments, since assessments aren’t standardised. Congratulations on your awesome achievement!