Question 849337
Find two values of &#952;, 0 &#8804; &#952; < 2&#960;, that satisfy the given trigonometric equation.
cos &#952; = &#8722; 1/2
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arccos(-1/2) = 180-60 = 120 degrees = (2/3)pi
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OR 
arccos(-1/2) = 180+60 = 240 degrees = (4/3)pi
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Cheers,
Stan H.