Carrotsticks' Solutions 2015 Extension 2 HSC (1 Viewer)

My two cents

New Member
Thanks Carrotsticks Can you also please up the paper

leehuan

Well-Known Member
Thanks Carrotsticks Can you also please up the paper

Pingas

m_wahwah

Member
I think you have Question 2 wrong? It should be a, B gives you 7+24i

Ekman

Well-Known Member
For Question 2 of MC I got A not B. Reason being is because when you say (x+iy)^2 = 7-24i, x^2-y^2 = 7 and 2xy = -24. So both x and y cant be negative at the same time otherwise you cant get -24. Hence B is wrong.

camdaman12

Member
also question 11 i isnt there a 5 on the bottom not 3

atargainz

Active Member
small algebra mistake in the denominator for 11)a)

turnerloos

TAFE Executive Officer
lets see how fucked i am...

m_wahwah

Member
also question 11 i isnt there a 5 on the bottom not 3
Yep he just didnt square the 2

Simplyy

New Member
umm, MCQ 2.A? Isn't it? B) doesn't work cause, for example, if you sub it in, (-4-3i)^2 = 16-9+24i = 7+24i not 7-24i.
Or if you prefer the longer method, of equating real and imaginary components/completing the square, x^2-y^2 = 7, 2ixy = -24, xy = -12, by inspection, x=4, y=-3 or x=-4, y=3. Therefore, z = 4-3i (A) or -4+3i...

leehuan

Well-Known Member
12 a) (iii)

I think it was z^2 - conjug(z)
Not conjug(z^2)

Carrotsticks

Retired
Fixed the errors!

Funnily enough, those were pretty much the exact same errors I made when I did my Extension 2 HSC.

lekawaiicupcake

New Member
Hey man thanks for doing this
One thing though, question 12 a) iii) asks for z^2-z(conjugate), not z^2-(z(conjugate))^2

(Also sorry for the formatting.)

Edit: Looks like someone else beat me to spotting it ^^

tywebb

dangerman
Thanks Carrotsticks Can you also please up the paper
He doesn't need to.

http://community.boredofstudies.org...maths-extension-2-thoughts-6.html#post7054013

Also there also a better quality one from WhoStanLeee in this post: http://community.boredofstudies.org...maths-extension-2-thoughts-8.html#post7054201

It's better quality but unfortunately is missing some bits (Q11 and 15 b and c - see below in post #24 in this thread for those which I extracted from beanbean's version).

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dandiclover

New Member
q11 a, denominator should be 5
q11 b, arg should be 5pi/6

Simplyy

New Member
umm, for 11. b) ii) argz = pi - arg(1/sqrt3) = pi - pi/6 = 5pi/6 not 2pi/3

Carrotsticks

Retired
Have updated the link! Cheers for pointing out those errors. Silliest of things.

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