(1)求H1,作A2=H1A。 1°G,=sign(分小 2l1=a1+O1=4,2=2,=(4,2,2) 3p1=a1=3×4=12 1-2-2 12 22-1(1) 求 H1 ，作 A2 = H1 A。 1 sign ( )( ) 3; 2 3 1 1 2 1 = 11  1 = i=  a ai  2 4, 2, (4,2,2) ; 1 11 1 2 T u = a + = u = u =  3 3 4 12; 1 =1 u1 =  =            = − = − 3 1 2 2 2 1 1 2 2 3 1 1 1 1 - - - - - - - H I uu T 