Q10 of 142 Page 11

Write the number of values of x in [0, 2 π] that satisfy the equation

1-cos2x-cos x=0.25


cos x 2x+cos x-0.75=0


Solving the quadratic equation we get


cos x = 0.5


cos x = cos60°



x=60° when n=0


And x=300° when n=1


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