Maths Extension 2 thoughts (4 Viewers)

[RealiseNothing]

The inequality was something called the QM-GM which is just the AM-GM extended to the QM-AM-GM-HM but without the AM and HM.

This is a really nice way of showing the extended version, using a circle and chords.

http://www.artofproblemsolving.com/..._Mean-Geometric_Mean-Harmonic_mean_Inequality

 

[Bozzin8R]

To put things in perspective. My goal HSC mark for Ext 2 was 85, and I thought this exam was much harder than previous years. Hopeful of around 52-53 raw, what do people think that will align to?

 

[laters]

How to do 16b) (iii) and (iv)

(iii) - If you tried solving for 0, you found that all of the roots were cos .........
So you just took the product of roots from there

(iv) x = 1/sqrt2

How did you do product of roots? It was like constant/leading coefficient but I couldn't find the leading coefficient properly (it was the LHS of part iv which was probably on the wrong track)

 

[coz707]

I feel like I could have attained full marks from Q11-14.
Then 15 I got max 9 and 16 max 6.
Currently sitting at 85 without silly mistakes, so right now worried about E3/4 cut off.

 

[leehuan]

That happy moment when seeing

I was embarrassed cause I forgot how to do that for ages. But eventually I got it out too

 

[RealiseNothing]

To put things in perspective. My goal HSC mark for Ext 2 was 85, and I thought this exam was much harder than previous years. Hopeful of around 52-53 raw, what do people think that will align to?

Probably around low to mid 80's depending on cut-offs.

 

[Drsoccerball]

How did you do product of roots? It was like constant/leading coefficient but I couldn't find the leading coefficient properly (it was the LHS of part iv which was probably on the wrong track)

You had to find the two general solutions and find all the roots and there was only one value with a constant and since the polynomial was even you don't have to put a negative in front.

 

[Drsoccerball]

Whats the state rank mark?

 

[JavaScript]

Whats the state rank mark?

99?9

 

[QuantumRoulette]

Can someone pm me the paper?

 

[leehuan]

Btw, I was panicking. I used the same method for Q16 b) (i) and (ii)....?!


Total outcomes: (np p) easy
Favourable outcomes: Well if you have n rows and p columns (or other way around I forgot......) and you could only put one black counter in each column then it has to be n^p

...Works for (i) too?

 

[Zen2613]

How did you do product of roots? It was like constant/leading coefficient but I couldn't find the leading coefficient properly (it was the LHS of part iv which was probably on the wrong track)

Not sure if I'm correct but I got (-1)^n.
Its because the product of roots relates to the constant term (independant of x). And since the entire thing went something like x^2n + x^2n-2 + ... + (1-x^2)^n, you only had to consider the last term to get the constant coefficent because all the others were multiplied by some x term.

 

[AntarcticMonkeys]

What did you guys get for question 10? I got C, I got the principle behind it but idk if I miscounted. Also I ended up using 15 booklets lol.

 

[Drsoccerball]

Not sure if I'm correct but I got (-1)^n.
Its because the product of roots relates to the constant term (independant of x). And since the entire thing went something like x^2n + x^2n-2 + ... + (1-x^2)^n, you only had to consider the last term to get the constant coefficent because all the others were multiplied by some x term.

Did you mention that it was an even polynomial and therefore the last term is the positive of what it is ? I think if they mark strict you may lose a mark.

 

[leehuan]

Oh wait, whoops, I think I threw too many x's around, -1 mark then for me.

 

[Thjv]

What did you guys get for question 10? I got C, I got the principle behind it but idk if I miscounted. Also I ended up using 15 booklets lol.

I think the answer was D or something

I used the sum of arithmetic progression from 1 to 101 and got one of the answers

 

[My two cents]

Was pretty happy with the exam: fairly easy However question 16 tough omg.

 

[jeremydang]

thank the lord for no circle geo!!

Any of you guys manage to get the lim(n->infin) P_n thing in q16?? was the only question I couldn't figure out how to get

No they are rude to get rid it. I managed to get every circle geo questions in the past paper in a very short time.
I blanked out for the whole banked track question, pros getting bad for this

 

[RealiseNothing]

I just want to know what lim n->infinity n^p/(npCp) is


Sent from my iPhone using Tapatalk

The way you do this using the question:

You want n to go to infinity, this means that there are infinite amount of rows.

So what happens is when you put a black counter in a column, you dont actually change the amount of spaces left in that column since there are an infinite amount of spaces.

So if you want a black counter in every column you just started placing them.

Ways to place first counter? just since there are q columns without a black counter (i.e. all of them)

Second counter? Any column but the one you just chose so

Third counter is and so on.

So the limit is just

I don't know if they will accept Integrand's answer simply because its a fairly easy Q16 and they might want you to use the previous parts. Not sure on this though so don't worry.

 

[Drsoccerball]

I think the answer was D or something

I used the sum of arithmetic progression from 1 to 101 and got one of the answers

me and ekman got C