• Congratulations to the Class of 2024 on your results!
    Let us know how you went here
    Got a question about your uni preferences? Ask us here

General Thoughts: Mathematics Ext 1 (3 Viewers)

AlexJB

Unmotivated
Joined
Jul 31, 2008
Messages
59
Gender
Male
HSC
2009
yer i couldnt find the area... :(

tan60 = o/h
o = h * sqr.rt(3)

Area of total triangle = 2 * (0.5 oh)
= oh
= h^2 * sqr.rt(3)

Volume = 10h^2 * sqr.rt(3)

---

I think that was the answer.
 

untouchablecuz

Active Member
Joined
Mar 25, 2008
Messages
1,693
Gender
Male
HSC
2009
hey guys i got pi/4n for 5a)iv)
dx/dt = nroot(a^2-x^2)
then sin-1 (x/a) = nt
then x= asin(nt)
then particles speed is half maximum speed at (a/root2)
so sub a/root2 in then you get pi/4 = nt no?
i got

x=asin(nt)

v=ancost(nt)

max v = an

.'. an/2 = an cos(nt)

cos(nt) = 1/2

t=pi/(3n)
 

copeys

Member
Joined
Nov 16, 2008
Messages
91
Gender
Male
HSC
2009
You had to find the area of the triangle and then just multiply by 10.

This is what I did: was isoceles. Construct a line through the middle, form 2 equal right angled triangles. We know the height is h, and we know the angles of the triangle. Use trig to find out the length of the base of the triangle. That gives you 2 sides, which you can use to find the area, which you just multiply through by 10.
Did exactly that :)
 

mitchwong650

Member
Joined
Apr 13, 2009
Messages
52
Gender
Undisclosed
HSC
2009

tan60 = o/h
o = h * sqr.rt(3)

Area of total triangle = 2 * (0.5 oh)
= oh
= h^2 * sqr.rt(3)

Volume = 10h^2 * sqr.rt(3)

---

I think that was the answer.
Exactly what i did.


Q1-4 only took around 30 minutes, Q 5 things started going down hill, but things got a bit better with the projectile question..

binomials raped me hard (except induction i think i got that)

hoping for 60+/84
 

micuzzo

Member
Joined
Aug 31, 2008
Messages
489
Gender
Undisclosed
HSC
2009

tan60 = o/h
o = h * sqr.rt(3)

Area of total triangle = 2 * (0.5 oh)
= oh
= h^2 * sqr.rt(3)

Volume = 10h^2 * sqr.rt(3)

---

I think that was the answer.
looks good... i tried it too.... n failed!
 

lychnobity

Active Member
Joined
Mar 9, 2008
Messages
1,292
Gender
Undisclosed
HSC
2009
For 5biv) what did everyone get?

I had k in my answer everywhere for some reason...

And 6aiii) where did you have to substitute?

6biii) no idea how to get (2n-1)

7cii) Didn't even get to do it.

Other than that, everything else was good.
 

imoO

Member
Joined
Apr 6, 2008
Messages
302
Gender
Male
HSC
2009
I just hope I am still in the top 30% of the state so I can get the ATAR I wanted.
 

AlexJB

Unmotivated
Joined
Jul 31, 2008
Messages
59
Gender
Male
HSC
2009
For 5biv) what did everyone get?

I had k in my answer everywhere for some reason...

And 6aiii) where did you have to substitute?

6biii) no idea how to get (2n-1)

7cii) Didn't even get to do it.

Other than that, everything else was good.
5biv, think it was just k?
6aii, equate the 2 y equations, you're able to find an expression for t and show that that value equaled th4e value in part i.
7cii, lost a couple of marks on 7c, going to go do it again in a bit, will get back to you if nobody else has.

Oh, and 6biii, I think you had to split it up in to two separate series, use the result in part i, then simplify? Pretty sure that's what I did, and the answer came out nicely.
 

kanux

Member
Joined
Sep 7, 2008
Messages
65
Gender
Female
HSC
2009
Q 1-4 was surprisingly easy
got screwed over for 5, 6, 7 ><"
 

buildabridge

Member
Joined
Jun 6, 2009
Messages
33
Gender
Female
HSC
2009
It was harder than the past papers I've done but ok I guess. It seemed very long, like usually I would finish in 80 mins and it took me half an hour longer today.
I'm thinking around 75/84.
 

liz91

New Member
Joined
Oct 19, 2007
Messages
6
Gender
Female
HSC
2009
As soon as we got out I just looked at my friends and started laughing.....ah it was SO bad it was funny - THIS is EXACTLY why 13 units is a good idea :)

What did people get as the max value of theta in the first part of question seven? I'm not sure my derivation was right - ahhhhh inverse trig functions drive me crazy!

Woah. I never have to do any ever again. Compensating factors!
 

5647382910

Member
Joined
Aug 6, 2008
Messages
135
Gender
Male
HSC
2010
im pretty sure ill get 75+ with max at 80/84

That tank q (5b) screwed me for some reason :(
Was the max value of theta sqrt(a(a + h)) for q 7bii? was 7cii sqrt(ah)?
also, could someone please explain why if P is on T, theta is max
 
Last edited:

lychnobity

Active Member
Joined
Mar 9, 2008
Messages
1,292
Gender
Undisclosed
HSC
2009
As soon as we got out I just looked at my friends and started laughing.....ah it was SO bad it was funny - THIS is EXACTLY why 13 units is a good idea :)

What did people get as the max value of theta in the first part of question seven? I'm not sure my derivation was right - ahhhhh inverse trig functions drive me crazy!

Woah. I never have to do any ever again. Compensating factors!
I got 1 + square root of something
 

untouchablecuz

Active Member
Joined
Mar 25, 2008
Messages
1,693
Gender
Male
HSC
2009
im pretty sure ill get 75+ with max at 80/84

That tank q (5b) screwed me for some reason :(
Was the max value of theta sqrt(a(a + h)) for q 7bii? was the final 7cii sqrt(ah)?
also, could someone please explain why if P is on T, theta is max
for 7 c) ii)

let O be the bottom of the wall

OT2=OR*OQ

OT2=h(a+h)

OT=√h(a+h), OT>0
 

Users Who Are Viewing This Thread (Users: 0, Guests: 3)

Top