... , ; , ,,; , , ;, ,,; , , ;2122112122222112211122111112/25/20081 Nguyễn Quang Minh ()( )( )===0, ,, 0, ,,0, ,,21212211nrnnLLLLLLLLLϕϕϕ12/25/200811−−=⇒=−+=−+=+=+−−003.0002.042240003.0002.042240003.0002.01010110101100000100000200000100000111100001111212121KKKKKK0WKBBP0WNKT1====−−=⇒−−0.001330.001330.0003260.001167-0.001167-0.001330.001167-101011010110000010000020000010000010.001330.001167-003.0002.042241121KBPVTKK12/25/20089235=−=r1h2h3h0002.00)010.3007.2005.1(321321=+++=−++++vvvvvv235=−=r1h2h3h0003.00)504.1503.1010.3(543543=−++=++−+++vvvvvv12/25/200810−====+003.0002.0;;111000011154321WvvvvvVB0WBV=1000001000005.0000001000001P12/25/200840 ... 24 1.503 15 1.504 11h2h3h4h5hA12312/25/20083 Dùng khai triển Taylor, giữ ñến số hạng bậcnhất: Áp dụng cho các phương trình ñiều kiện, chúng ta sẽ có:( )()0 , ,,, ,,221111211211=+∂∂+∂∂+=...