定积分问题,∫ (上π/2下0) (tanx)^2009 /(tanx)^2009+1

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定积分问题,∫ (上π/2下0) (tanx)^2009 /(tanx)^2009+1
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定积分问题,∫ (上π/2下0) (tanx)^2009 /(tanx)^2009+1
定积分问题,∫ (上π/2下0) (tanx)^2009 /(tanx)^2009+1

定积分问题,∫ (上π/2下0) (tanx)^2009 /(tanx)^2009+1

可以不用这么麻烦,开始时就可以换元了。令x = π/2 - u,dx = - du当x = 0,u = π/2,当x = π/2,u = 0K = ∫(0→π/2) lntanx dx= ∫(π/2→0) lntan(π/2 - u) (- du)= ∫(0→π/2) lncotu du= ∫(0→π/2) lncotx dx = KK + K = ∫(0→π/2) lntanx dx + ∫(0...

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可以不用这么麻烦,开始时就可以换元了。令x = π/2 - u,dx = - du当x = 0,u = π/2,当x = π/2,u = 0K = ∫(0→π/2) lntanx dx= ∫(π/2→0) lntan(π/2 - u) (- du)= ∫(0→π/2) lncotu du= ∫(0→π/2) lncotx dx = KK + K = ∫(0→π/2) lntanx dx + ∫(0→π/2) lncotx dx2K = ∫(0→π/2) (lntanx + lncotx) dx2K = ∫(0→π/2) ln(tanx · cotx) dx2K = ∫(0→π/2) ln(1) dx2K = 0==> K = 0

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