内积的运算性质 (其中x,y,z为n维向量,为实数) (1)[x,y=[y,x (2)x,y =alx,y5 (3)[x+y,z]=[x,z+[y, (4)x,x≥0,且当x≠0时有x,x]>0.内积的运算性质 (其中x, y,z为n维向量,为实数): (1) x, y =  y, x; (2) x, y = x, y; (3) x + y,z = x,z + y,z; (4)[x, x]  0,且当x  0时有[x, x]  0