Question

Sa se rezolve in Mulțimea numerelor reale ecuația sin 2x = cos x

Answer 1

sin2x-cosx=0
2sinxcosx-cosx=0
cosx*(2sinx-1)=-
cosx  =0
x=π/2
Solutia   grnerala
x1=+/-π/2+2kπ2
2sinx-1=0
2sinx=1   sinx=1/2
x=π/6
x=(-1)^k*π/6+kπ
solutia   grnrtala
x={π/2+2kπ}U{(-1)^k*π/6+kπ}