# math !!

solve the equation for the interval
0<x<2pie

cos^2 x + 2cosx + 1 = 0

1. 👍 0
2. 👎 0
3. 👁 43
1. cos^2 x + 2cosx + 1 = 0 factors to
(cos x + 1)^2 = 0
cos x + 1 = 0
cos x = -1
x = PI

1. 👍 0
2. 👎 0
posted by Reiny

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