According to the triangle rule of vector, draw a triangle with an angle equal to 60, its opposite side is 1 and its adjacent side is X (x(x>0)).

The other is y (y(y>0)

From cosine theorem, 1=y? +x？ -2 xycs 60

x？ -yx+y？ - 1=0

△=y？ -4(y？ - 1)≥0

The solution is 0 < y < 2 times the root number 3/3.