Share your Multiple Choice answers (1 Viewer)

lulwut

New Member
Joined
Aug 7, 2013
Messages
22
Gender
Male
HSC
2013
I'm hoping I got all 10 correct (aren't we all):

1)c
2)d
3)c
4)d
5)a
6)b
7)a
8)d
9)b
10)c
 

lulwut

New Member
Joined
Aug 7, 2013
Messages
22
Gender
Male
HSC
2013
6a was the general formula one right?

2x should = the general formula i think, so i figured x= (general formula) / 2
 

Mitsunami

Member
Joined
Dec 7, 2012
Messages
52
Gender
Male
HSC
2013
1) c
2) d
3) b
4) d
5) a
6) d
7) a
8) d
9) b
10) c

Realized 6 was wrong after the examiners say the exam's over. *sigh*
 

RealiseNothing

what is that?It is Cowpea
Joined
Jul 10, 2011
Messages
4,591
Location
Sydney
Gender
Male
HSC
2013
6a was the general formula one right?

2x should = the general formula i think, so i figured x= (general formula) / 2
The general formula has a though, so when you divide by the 2 you just get
 

alexandred

New Member
Joined
Nov 8, 2011
Messages
29
Gender
Male
HSC
2013
6 is b. Consider the graph of y=sinx; for any given vertical line y=a (|a|<=1) the solutions for intersections are: x = 2kpi + arcsin(a), x = (2k+1)pi - arcsin(a), or equivalently x = kpi + (-1)^k*arcsin(a). Divide this by 2 for 2x
 

RealiseNothing

what is that?It is Cowpea
Joined
Jul 10, 2011
Messages
4,591
Location
Sydney
Gender
Male
HSC
2013
Cambridge 3U year 12, page 33:

"The general solution of is "

Divide by 2 gets A doesn't it?
 

lulwut

New Member
Joined
Aug 7, 2013
Messages
22
Gender
Male
HSC
2013
The general formula has a though, so when you divide by the 2 you just get
general formula is just pi not 2pi for sin though. and its sin^-1(a) not just a, so sin^-1(a) represents 2x which when divided by 2 is equal to x, which works with the general formula where you have to have the angle at the end. I'm pretty sure it's A) now.
 

lulwut

New Member
Joined
Aug 7, 2013
Messages
22
Gender
Male
HSC
2013
general formula is just pi not 2pi for sin though. and its sin^-1(a) not just a, so sin^-1(a) represents 2x which when divided by 2 is equal to x, which works with the general formula where you have to have the angle at the end. I'm pretty sure it's A) now.
Im back to thinking it's B) again.. LOL

sin(2x)=a so arcsin(a)=2x

but lets do it in general for sinx first. Sinx=sina so x=a

x=npi+(-1)^n*a

sub in x as 2x and a as arcsin(a)

2x=npi+(-1)^n*arcsin(a)

so x=(npi+(-1)^n*arcsin(a)) / 2 which is answer b)
 

kewon

Member
Joined
Feb 9, 2011
Messages
72
Gender
Male
HSC
2013
Im back to thinking it's B) again.. LOL

sin(2x)=a so arcsin(a)=2x

but lets do it in general for sinx first. Sinx=sina so x=a

x=npi+(-1)^n*a

sub in x as 2x and a as arcsin(a)

2x=npi+(-1)^n*arcsin(a)

so x=(npi+(-1)^n*arcsin(a)) / 2 which is answer b)
pls be b...
in the test i was thinking dam could be a trick and could be a but i cbf spending more time on it so i just hoped for the best...
 

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

Top