Respuesta :

Use cos2x =1-2sin^2x

1+sinx- (1-2sin^2x) = 1+ sinx -1+2sin^2x

=sinx+2sin^2x=sinx(1+2sinx)

Therefore

Either sinx=0 or 1+ sin2x =0

X=npi or sin2x=-1

Sin2x=sin 3pi/2

2x= npi +(-1)^n3pi/2

x=npi/2 + (-1)^n 3pi/4