Because the quadrilateral formed by the sum of two unit vectors is a rhombus, and the diagonal in this question is with BD***, the quadrilateral in this question is a rhombus, the side length of the unit vector is 1, and the diagonal of the rhombus formed by the sum of the two unit vectors is the root number 3, so the angle b is 60.

Because AB= root number 2, the area of the diamond can be obtained as root number 3.