(4)>anMM显著增长,而N增长缓慢些 1≠0M>Oo (0 0B1+62>90W=90 z,0(o)=%1-1-2<0 o→∞,B+0,→180 o(jo)→-90 0(i0) M2→>∞0 |(o)→09  1 z 1 p p2 0 j ( ) 0 ( ) 90 , 180 ( ) 0 90 90 0 1 2 0 0 1 2 1 1 2 0 1 0 1 2 1 1 0 → →  → − →  + → = − −  +  =                  Z j M M j j z N 0 Z( j)  0  0 90 0 −90 ( j) G 1 0 (4)   M1 M2 显著增长，而 N1 增长缓慢些