• Best of luck to the class of 2019 for their HSC exams. You got this!
    Let us know your thoughts on the HSC exams here
  • Like us on facebook here

Solutions (1 Viewer)

Alex222

New Member
Joined
Oct 24, 2003
Messages
3
Ok i probably shouldnt be the one to be doing this, because i'm not expecting great great great things - but here are my solutions. Pleease tell me what you guys got the same or different!

Question 1 -
a) -1, 4.5
b) x<2, x>=5
c) 1.5
d) y = 12xsquared
e) 6/25

Question 2 -
a) Graph
b) x/(1 + x squared) + tan`x
c) 1
d) 80
e)i) root2cos(x + pi/4)
ii) Graph

Question 3 -
a) 30240
b) i) because its in the form - n squared x
ii) y=4
iii) pi
c) i) explanation
ii) .01784
d) Proof

Question 4 -
a) 3003
b) Not sure what i wrote?
c) 19
d) i) because it has four verteces which are concyclic
ii) because its opposite angles are supplementary
iii) proof
iv) proof

Question 5 -
a)1/12 sin6x + .5x + c
b)i) not pass horizontal line test
ii)graph
iii) x>1 (or equal to!)
iv) ????
c)i) proof
ii) b = 480
iii) 500 degrees

Question 6 -
a) i) proof
ii) pi/10
b) ???????

Question 7 -
a) distance is 2798.96 and bearing is 208 degrees
b) proof/proof/ ???


No laughing please guys! haha
 

Constip8edSkunk

Joga Bonito
Joined
Apr 15, 2003
Messages
2,398
Location
Maroubra
Gender
Male
HSC
2003
5c)iv) solve the quadratic formed when u switch the y with the x, take the value thats smaller than 2
6 b) i got something like root2 - 1 and then 2 - root 2
7a) i got 2000 something meters and 256 degrees i think
b)iii) dun think many ppl got the whole thing out, i only got the last part not the 1st eqn... time ran out
 

nerdd

Member
Joined
Feb 13, 2003
Messages
345
4c i got k to be 13....
and 7a i got the distance to be 1703 m and the bearing to be like 182 degrees or something like that..
 

Constip8edSkunk

Joga Bonito
Joined
Apr 15, 2003
Messages
2,398
Location
Maroubra
Gender
Male
HSC
2003
hahaha

for q4 c), i had a*(1/a)*b = -6/2 .'. b = -2 :rolleyes: ...2 marks down the drain....:(

but yeah b=-3 --> 2*-27 + 9+3k+6=0
.'.3k = 39 --> k=13
 

iambored

dum-di-dum
Joined
Apr 27, 2003
Messages
10,868
Location
here
Gender
Undisclosed
HSC
2003
Originally posted by Alex222
Question 1 -
c) 1.5
d
sis u get that with 3/2 x/sinxcosx
then transfering it to x/sinx * 1/cosx
which then gave 3/2 *1*1?
 

iambored

dum-di-dum
Joined
Apr 27, 2003
Messages
10,868
Location
here
Gender
Undisclosed
HSC
2003
Originally posted by iambored
sis u get that with 3/2 x/sinxcosx
then transfering it to x/sinx * 1/cosx
which then gave 3/2 *1*1?
i got the same answer as you, but i am wondering if my working was right

so what i did was changed the bottom to 2sinxcosx
then i took out the 2 (and the 3 on the top)
and then i changed the x/sinxcosx to x/sinx multiplied by 1/cosx
and therefore, x/sinx = 1, and 1/cosx =1
so i was left with 2/3 as my answer

i can't remember what i got for the others without looking at the paper properly, but i know i got the same for 1b)
 
Last edited:
N

ND

Guest
It was lim(3x/sin2x), so all you have to do is take 3/2 outside, i.e. lim((3/2(2x/sin2x)), and remember that lim(ax/sinax)=1, so lim(3/2(2x/sin2x))=3/2.

note: i wrote just 'lim' instead of 'lim x->0'.
 

smeyo

Member
Joined
Sep 16, 2003
Messages
164
Location
hunter valley
the idea of that question is as x approaches 0, sinx approaches x therefore 3/2*2x/sin2x will give 3/2*2x/2x = 3/2*1 = 3/2
 

iambored

dum-di-dum
Joined
Apr 27, 2003
Messages
10,868
Location
here
Gender
Undisclosed
HSC
2003
Originally posted by smeyo
the idea of that question is as x approaches 0, sinx approaches x therefore 3/2*2x/sin2x will give 3/2*2x/2x = 3/2*1 = 3/2
!! and u know, i looked at that question to do it like that for so long. well mine still worked, in a way, i hope i get the marks
 

braindrainedAsh

Journalist
Joined
Feb 20, 2003
Messages
4,269
Location
Sydney
Gender
Female
HSC
2003
Yay I got the Newton's Law one right and my 4 unit friend didn't get it! I feel smart-ish!
 

deyveed

School Leaver
Joined
Oct 13, 2002
Messages
639
Gender
Male
HSC
2003
What did you get for the Newton's method one?
I had:

f(x) = sinx - 2x/3
f(1.5) = -0.974
f'(x) = cosx - 2/3
f'(1.5) = 0.333

x_2 = 1.5 + 0.974/0.333
x_2 = 4.4

How is that close to 1.5?
 

walla

Satisfied Customer
Joined
Nov 9, 2002
Messages
285
Gender
Male
HSC
2003
yeah i got something really close to 1.5 for newton's
 

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top