(v(=)+6.)(V()+6.))+ivr-0 V"=0 (T()+=0→T)+'=C ()-0.)C i.V(=)+6.)r'=E ve- 晋* 八d1 过物点的轨迹在x=0时=0，故 代入位场表达式即得，( ( ) )( ( ( ) ) ) ( ( ( ) ) ) ( ( ) ) ( ) ( ) ( ( ) ) ( ( ) ) ( ) 0 0 0 0 0 0 0 0 1 0 4 0 0 0 0 0 1 d 1 1 2 2 d d z z z z r r z r z z z r z r z A z z z A A r r r z r z z A A A A z z V z V z r V r V V z r V z r C v v V r C v v V z r r z V z V V z z d d d V V r z z z z V V V d V d z z d d                     + + + =    =   + =  + =     = =  + =  = + =     = = = + = + −             + +        ＝ ， ＝     