Im working some sin addition formulas and i dont understand why answer is subtraction. | Mathematics | Page 1

zealous pagoda Jul 4, 2024, 3:11 PM

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im using khan academy to refresh my trig and precalc topics for a university placement test. thanks for your help.

latent cipherBOT Jul 4, 2024, 3:11 PM

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unkempt escarp Jul 4, 2024, 3:18 PM

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@zealous pagoda They're using the identity: cos(a + b) = cos(a)cos(b) - sin(a)sin(b)

zealous pagoda Jul 4, 2024, 3:18 PM

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i see that its cos now

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i had a bunch of sin problems in a row and got tunnel vision

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thanks @unkempt escarp

unkempt escarp Jul 4, 2024, 3:19 PM

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np

latent cipherBOT Jul 4, 2024, 3:25 PM

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If you are done with this channel, please mark your problem as solved by typing .close

marsh hinge Jul 5, 2024, 2:59 AM

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.close

ember copper Jul 8, 2024, 9:59 PM

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its d.

#Im working some sin addition formulas and i dont understand why answer is subtraction.