Find all solutions to the equation.
cos^2x + 2 cos x + 1 = 0 (4 points)
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Answer:
cos^2x + (1+1)cos x + 1 = 0
or,cos^2x + cos x + cos x + 1 = 0
or,cos x(cos x + 1) + 1 (cos x + 1) = 0
or, (cosx + 1) + (cosx + 1) = 0
either
cosx + 1 =0 or cosx +1 =0