返回上页 下页因为所以证明 du(x?y)?P(x?y)dx?Q(x?y)dy?其中
u ( x? y ) ),( ),(
00
),(),(yx yx dyyxQdxyxP?
u ( x? y ) ),( ),(
00
),(),(yx yx dyyxQdxyxP
xxyy dxyxPdyyxQ 00 ),(),( 0?
),(),(),(
00
0 yxPdxyxPxdyyxQxx
u x
x
y
y
类似地有 ),( yxQyu 从 而 du ( x? y )? P ( x? y ) dx? Q ( x? y ) dy?
返回
u ( x? y ) ),( ),(
00
),(),(yx yx dyyxQdxyxP?
u ( x? y ) ),( ),(
00
),(),(yx yx dyyxQdxyxP
xxyy dxyxPdyyxQ 00 ),(),( 0?
),(),(),(
00
0 yxPdxyxPxdyyxQxx
u x
x
y
y
类似地有 ),( yxQyu 从 而 du ( x? y )? P ( x? y ) dx? Q ( x? y ) dy?
返回