南宁的鹰
幼苗
共回答了18个问题采纳率:88.9% 举报
∫(sinx+cosx)dx/[(sinx)^3 cosx]
=∫dx/[(sinx)^2 cosx]+∫dx/(sinx)^3
=-∫dcotx/cosx +∫dx/(sinx)^3
=-cotx/cosx - ∫cotxsinxdx/(cosx)^2 +∫dx/(sinx)^3
=-1/sinx-∫dx/cosx+∫dx/(sinx)^3
=-1/sinx-ln|secx+tanx|+(-1/2)cosx/(sinx)^2+(-1/2)ln|cscx+cotx|+C
∫dx/(sinx)^3=∫d(-cotx)/sinx=-cotx/sinx-∫cotxcosxdx/sinx^2=-cosx/sinx^2-∫cotx^2dx/sinx
=-cosx/sinx^2-∫dx/sinx^3 +∫dx/sinx
2∫dx/(sinx)^3=-cosx/sinx^2-ln|cscx+cotx|
∫dx/sinx= -∫dcosx/(1-cosx)(1+cosx)=(-1/2)ln|(1+cosx)/(1-cosx)|=-ln|(1+cosx)/sinx|=-ln|cscx+cotx|
1年前
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