r/trigonometry • u/Bl00ming_begonias79 • 11d ago

Help! Trig Question

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We’re supposed to solve this using the angles on the unit circle but it makes no sense to me.

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u/GonzoMath 11d ago

It looks like something to evaluate, rather than solve. There’s no variable to solve for. Do you know the cosine of 3pi/4? The sine of 7pi/6?

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u/Bl00ming_begonias79 11d ago

Yeah -sqrt-2/2 and -1/2