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use the appropriate trig identity (sum and difference, half angle, double angle) to find the exact value. 1)cos 255 degrees
2) sin 165 degrees
3) tan 285 degrees

  • Trigonometry -

    isn't 255 = 180+75=270-15 which is 270-30/2?

    isn't 165=180-30/2

    isn't 285=270+30/2?

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