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what is the exact value of sin^2 pi/6-2 sin pi/6 cos pi/6 +cos^2 (-pi/6)?

a) 2- sqrt 3
b) 2- sqrt 3/ 2
c) 2+ sqrt 3/2
d) 2+ sqrt 3

I am not sure how to work this out and would appreciate you how to show me the process. Thank you in advanced!!!!!!!

  • TRIG -

    sin pi/6 = sin 30 deg = 1/2

    cos pi/6 = .5 sqrt 3

    cos -x = cos x
    so

    1/4 - .5 sqrt 3 + 3/4

    1 - .5 sqrt 3

    (2 - sqrt 3 ) / 2

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