《数学物理方程》补充1

u u+△u h pag 2 V→V+△hdl M M n+△uhd M 10(1+△uhd/1)(1+△/△x) M (1-△a/△x)=P0(1 X x+△X △x h p, dg hdg 2po(1-)f=n pdg hdg △ △ o(1+ 2 △x 2 2 △ △=12-f=hgpo

x x+Δx u u+Δu 2 2 h dg f  = V V uhd 0 0 → +  0 0 0 M M V V uhd   = → = +  0 0 0 0 0 (1 / ) (1 / ) (1 / ) (1 ) M M V uhd V V u x M u u x V x  = = +  +     −   = −  1 f 2 f 2 2 1 1 0 (1 ) 2 2 h dg h dg u f x    = = −  2 2 2 2 0 (1 ) 2 2 h dg h dg u f x    = = +  2 2 1 0 u f f f h dg x    = − = 