Question

a) 2cos x/3+1=0 (2cos de x supra 3 plus 1 egal cu 0)

Answer 1

2cosx/4=0   2cosx=o   cosx=o

cosx=o => x={arccoso+2kπ}∪{-arccos0+2kπ}={π/2+2kπ}∪{-π/2+2kπ}