解因 Ou Ov ax+By +av(x, y)e+ey=/Ov +av)e“x+B x +a ax+By tav)a ax+By OX (3+2a+av)e ax+By OX oul By+Bv(x, y)eax+p) Bv) By (2+2B+B2)l+B→ arion +(2a+k)-+(-2B+k))+(a2-B2+ka+kB)=014 ( , ) ( ) u v v x y x y x y e v x y e v e x x x            + + + =  + = +    解 因 2 2 2 2 ( ) ( ) u v v v x y x y e v e x x x x            + + = + + +      2 2 2 ( 2 ) v v x y v e x x       + = + +   ( , ) ( ) u v v x y x y x y e v x y e v e y y y            + + + =  + = +    2 2 2 2 2 ( 2 ) u v v x y v e y y y        + = + +     2 2 2 2 2 2 (2 ) ( 2 ) ) ( ) 0 v v v v k k k k v x y x y           − + + + − + + − + + =    