dIn u 1 aP aQ d o ay ax )=∫(x) ∴H(x)=e ∫f(x) b.当只与有关时:Q=0,Q=, ax 小y dhnp1QOP、 0)=8(y) 小 ,P ax a g(y)dy ∴(y)=e 上页b.当只与y有关时; ( ) ln 1 x Q y P dx Q d − = = f (x) ( ) . ( ) = f x dx x e = 0, x , dy d y = ( ) ln 1 y P x Q dy P d − = = g( y) ( ) . ( ) = g y dy y e