江画工太猩院 一般地 ∫(x)=l(x))(a(x)>0) nf(x)=v(x)·hmu(x) 又∷In∫(x) f(r) ∫(x) . f(r=f(r)In f(x) d x ∴f(x)=u(x)yy(x),hn(xn(x ux江西理工大学理学院 一般地 ( ) ( ) ( ( ) 0) ( ) f x = u x u x > v x ( ) ( ) 1 ln ( ) f x dxd f x f x dxd 又Q = ⋅ ( ) ( ) ln f (x) dxd ∴ f ′ x = f x ⋅ ] ( ) ( ) ( ) ( ) ( ) [ ( ) ln ( ) ( ) u x v x u x f x u x v x u x v x ′ ∴ ′ = ′ ⋅ + Q ln f (x) = v(x)⋅ lnu(x)