令x=tanθ,
则∫[xarctanx/√(1+x^2)]dx
= ∫θtanθsecθdθ =∫θd(secθ)
= θsecθ-∫secθdθ = θsecθ-ln|tanθ+secθ|+C
= arctanx*√(1+x^2)+ln[x+√(1+x^2)]+C
令x=tanθ,
则∫[xarctanx/√(1+x^2)]dx
= ∫θtanθsecθdθ =∫θd(secθ)
= θsecθ-∫secθdθ = θsecθ-ln|tanθ+secθ|+C
= arctanx*√(1+x^2)+ln[x+√(1+x^2)]+C