Trigonometry

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The question was:

"Given that sin theta is -1/2 and theta is in quadrant IV, find the cos and tan of theta."

I found 1/2 for cosine and -1 for theta, but the answer sheet said I was incorrect. I am almost positive I did this correctly... can someone double check for me?

  • Trigonometry -

    make a triangle, and you will see that
    y = -1, x = sqrt(3) and r = 2

    so cos(theta) = sqrt(3)/2
    tan(theta) = -1/sqrt(3) or - sqrt(3)/3

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