Find all solutions to the equation. cos2x + 2 cos x + 1 = 0

x = pi/2, 3pi/2  etc               x = pi, 3 pi, etc

Step-by-step explanation:

cos2x + 2 cos x + 1 = 0

           cos 2x = cos^2 - sin^2x  trig identity

cos^2x -sin^2 + 2cos x +1 = 0

rearrange

cos^2 x +2cos x + 1-sin^2 x = 0

       1 - sin^2 x = cos^2 x  trig identity

cos^2 x + 2 cos x + cos ^2 x = 0

combine like terms

2 cos ^2 x + 2 cos x = 0

divide by 2

cos ^2 x + cos x = 0

factor out a cos x

cos (x) (cos x +1) = 0

using the zero product property

cos (x) = 0       cos x + 1 =0

cos x =0         cos x = -1

taking the arccos of each side

arccos cos x = arccos (0)   arccos (cos x) = arccos (-1)

x = pi/2, 3pi/2  etc               x = pi, 3 pi, etc

true

step-by-step explanation:

according to the national european world center, the engineering of the ford company on elon musk's flame throwers proved the globalization of the natural wallabies and therefore, results in the growth product domestication in almonds.

c. 6tan80

step-by-step explanation: