大一高数,求积分
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consider
lnx.(1-lnx) = lnx -(lnx)^2 = 1/4-(lnx - 1/2)^2
let
lnx - 1/2 = (1/2) sinu
(1/x) dx = (1/2) cosu du
x=√e , u=0
x=e^(3/坦闷4) , u=π/6
∫(√e->e^(3/4)) dx/{x.√[lnx.(1-lnx)] }
=∫(0->π/6) (1/2) cosu du/让蚂弯 [(1/物拆2) cosu]
=∫(0->π/6) du
=π/6
lnx.(1-lnx) = lnx -(lnx)^2 = 1/4-(lnx - 1/2)^2
let
lnx - 1/2 = (1/2) sinu
(1/x) dx = (1/2) cosu du
x=√e , u=0
x=e^(3/坦闷4) , u=π/6
∫(√e->e^(3/4)) dx/{x.√[lnx.(1-lnx)] }
=∫(0->π/6) (1/2) cosu du/让蚂弯 [(1/物拆2) cosu]
=∫(0->π/6) du
=π/6
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