Question 601201
find all values of &#8854; in the interval 0°&#8804; &#8854; < 360° that satisfy the equation 2cosē&#8854; = cos &#8854; + 1 
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Sub x for cos(theta)
2x^2 = x + 1
2x^2 - x - 1 = 0
(2x + 1)*(x - 1) = 0
x = 1
cos = 1
theta = 90 degs
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x = cos = -1/2
theta = 120, 240 degs