#trig identities

17 messages · Page 1 of 1 (latest)

willow topaz Jun 10, 2023, 8:26 PM

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How do I solve this l? Cos3x is confusing me

mint dew Jun 10, 2023, 8:34 PM

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@willow topaz

willow topaz Jun 10, 2023, 8:36 PM

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How did you Do the second line?

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I don't get how you expanded cos(2x-x)

mint dew Jun 10, 2023, 8:38 PM

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willow topaz How did you Do the second line?

cos(2x+x)

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Not -

willow topaz Jun 10, 2023, 8:38 PM

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Ah okay how do you expand l?

mint dew Jun 10, 2023, 8:38 PM

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Recall cos(a+b) =cosAcosB-sinAsinB

willow topaz Jun 10, 2023, 8:38 PM

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Ahh

mint dew Jun 10, 2023, 8:38 PM

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A=2θ

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B=θ

willow topaz Jun 10, 2023, 8:38 PM

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Omg

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Thank you

mint dew Jun 10, 2023, 8:39 PM

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Yw gl on Tuesday

willow topaz Jun 10, 2023, 8:39 PM

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Thank you

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U too