Let x1,x2… ,xn are vectors set out from any vertex of n-simplex. The ineluded angle of xi and xj is aij , and G=(?)aij, the volume of this simplex is V. In this paper, we prove the inequality as below:(?) When n=2, the equality holds in (*) , when n≥3, the equality holds in (*) if {xi} is orthogonal set. |