max coefficient question - work out tk+1/tk or quote formula (1 Viewer)

[httton]

hey guys

do we lose marks if in probability or binomial a question asks us and we just use

n-k+1/n x b/a >1 ?

 

[barbernator]

nope, that is perfectly fine, but there is no point in using that formula unless you know how to derive it. There are many instances in greatest co-efficient where they can replace T(k+1)/Tk with Tk/T(k-1) or t(k+1)/tk, and this can change the result.

 

[httton]

wait so

use formula or not use formula?

 

[barbernator]

use formula, as long as you know how to derive it, and when and how to use it. Don't get caught out using it wrongly, when you could have easily taken a few steps of algebra to find the greatest coefficient

 

[httton]

oh cheers man thanks.

 

[Carrotsticks]

No, HSC does not accept the formula.

 

[mirakon]

Yeah, im pretty sure u have to derive it each time

 

[D94]

It's not very hard to just find T(k+1) and T(k). There are usually common factors which cancel out and you get a neat method and result.

 

[fortune_cookie]

They have never asked the question in an hsc. Go back 20years and it has never been asked in 3 unit. I think I saw once in a four unit paper.

Nevertheless, every time it asked in a trial paper they always break it into two parts.

a) show tk+1/tk = ............

b) Hence find greatest term.

So you cannot memorise the formula.

 

[iSplicer]

No, HSC does not accept the formula.

+1. I don't think it's even worth deriving that formula, just do it the 'normal' way quickly and clearly to ensure full marks.

 

[Alkenes]

So we have to derive the formula?

No, HSC does not accept the formula.

 

[Carrotsticks]

So we have to derive the formula?

Most certainly yes.

 

[Alkenes]

And you know for conics; we derive the equation of chord of an ellipse....we get a gradient something like b (sin theta + sin alpha)/ something

do we have to derive the equation of the sum and product of sin and cos or just use the formula like in 3 unit?

Most certainly yes.

 

[Carrotsticks]

You may use it as it is, but the HSC examination would not expect you to know it off by heart. If a question requires the use of the formula, then it will have the very first part being to prove it "Prove that XXXX"

 

[Alkenes]

if doesnt say the prove part, and question is worth say 2 marks, do we have to show how we derived that rule ??

You may use it as it is, but the HSC examination would not expect you to know it off by heart. If a question requires the use of the formula, then it will have the very first part being to prove it "Prove that XXXX"

 

[Carrotsticks]

if doesnt say the prove part, and question is worth say 2 marks, do we have to show how we derived that rule ??

Nope, you can go ahead and use it without proof.