(sinx)^2+cosx +1 = 0 , domain: [0,2pi)

Question

aydame por favor

gracias

Answer 1

1 - (cosx)^2 + cosx + 1 = 0
cos^2 - cos - 2 = 0
(cosx - 2)(cosx + 1) = 0

cosx no puede ser 2

cosx = -1

x = pi