4sen2x*(1-sen2x)= 1/4
4sen2x-4sen4x= 1/4
4sen4x-4sen2x - 1/4=0
(16sen4x-16sen2x -1)/4=0
16sen4x-16sen2x -1=0
t=sen2x
16t2-16t -1=0
t 1,2= (16±√(256-4*16*(-1)))/(2*16) = (16±(8√5))/32 = (2±√5)/4-----> t1= (2+√5)/4 , t2= (2-√5)/4
t1=sen2x=(2+√5)/4 -------> senx= ± √((2+√5)/4) -------> x1=arcsen(√((2+√5)/4)) , x2= arcsen (-√((2+√5)/4))
t2= sen2x=(2-√5)/4 -------> senx= ± √((2-√5)/4) -------> x3=arcsen(√((2-√5)/4)) , x2= arcsen (-√((2-√5)/4))