How do I find sin 120° ? | Mathematics | Page 1

potent cloakBOT Oct 30, 2023, 4:49 AM

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steel plaza Oct 30, 2023, 4:49 AM

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you know unit circle?

cloud zealot Oct 30, 2023, 4:49 AM

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Yes

steel plaza Oct 30, 2023, 4:50 AM

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okay

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draw it out

cloud zealot Oct 30, 2023, 4:50 AM

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Wait....

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Hello sir !

cloud zealot Oct 30, 2023, 4:53 AM

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steel plaza draw it out

Can't I write sin 120° as sin (90°+30°) ??

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And then sin 90° = 1 , sin 30° = 1/2
Sin 120° = 1 +1/2 ?

steel plaza Oct 30, 2023, 4:54 AM

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uhhh you can do sin(a+b)

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however that simplifies to something else

cloud zealot Oct 30, 2023, 4:54 AM

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Why ?

steel plaza Oct 30, 2023, 4:54 AM

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sinacosb+cosasinb or something

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idk

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there you go

cloud zealot Oct 30, 2023, 4:54 AM

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But why ?

cloud zealot Oct 30, 2023, 4:55 AM

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cloud zealot And then sin 90° = 1 , sin 30° = 1/2 Sin 120° = 1 +1/2 ?

Why this not

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Sorry for late

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Please help

steel plaza Oct 30, 2023, 5:11 AM

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cloud zealot But why ?

erm

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i forgot the explanation for double angle identities

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its a mess

steel plaza Oct 30, 2023, 5:11 AM

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cloud zealot

okay you know reference angle stuff right

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just draw 120 there and draw the hyp of your right triangle

gleaming hound Oct 30, 2023, 7:56 AM

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Wouldn't sin 120 = sin 60

#How do I find sin 120° ?