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Share your Multiple Choice answers (1 Viewer)

lulwut

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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

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6a was the general formula one right?

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

Mitsunami

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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

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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

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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

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Cambridge 3U year 12, page 33:

"The general solution of is "

Divide by 2 gets A doesn't it?
 

lulwut

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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

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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

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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...
 

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