C2 Trig Watch

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jamal1425
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#1
Report Thread starter 13 years ago
#1
This is a really simple, elementary question, but I'm not sure how one's supposed to go about doing things.


sin x° = -√3/2, -180 'less than or equal to' x 'less than or equal to 540'

-√3/2 is equal to -30° right? What do you do next? Use the cast method? I have, but I don't get the right answers, must be doing something wrong. :confused:
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J.F.N
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#2
Report 13 years ago
#2
arcsin-sqrt(3/2)=-60. So in the suggested interval, x=-120,-60,240,300
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iluvcheesecake
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#3
Report 13 years ago
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(Original post by jamal1425)
This is a really simple, elementary question, but I'm not sure how one's supposed to go about doing things.


sin x° = -√3/2, -180 'less than or equal to' x 'less than or equal to 540'

-√3/2 is equal to -30° right? What do you do next? Use the cast method? I have, but I don't get the right answers, must be doing something wrong. :confused:
sin^-1(-√3/2) = -60, not -30

I'm not sure what the cast method is :confused: , but I'd try drawing the graph y=sin x, and marking on the point where x=-60, then seeing what values of x, the y-value is the same. You should get -120,-60,240 and 300 in that range.
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jamal1425
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#4
Report Thread starter 13 years ago
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(Original post by iluvcheesecake)
sin^-1(-√3/2) = -60, not -30

I'm not sure what the cast method is :confused: , but I'd try drawing the graph y=sin x, and marking on the point where x=-60, then seeing what values of x, the y-value is the same. You should get -120,-60,240 and 300 in that range.
'Cast Method' , though I don't think thats the right name for it, is when you draw the 4 quadrants , 1st, 2nd, 3rd , 4th, etc. But I think the way you've suggested is alot simpler! Thanks!
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iluvcheesecake
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(Original post by jamal1425)
'Cast Method' , though I don't think thats the right name for it, is when you draw the 4 quadrants , 1st, 2nd, 3rd , 4th, etc. But I think the way you've suggested is alot simpler! Thanks!
Oh yeah, I know what you mean, sorry I was just being stupid. :rolleyes:
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