∫1/（sinxcosx）dx=∫[(sinx)^2+(cosx)^2]dx/(sinxcosx)=∫(tanx+cotx)dx=-ln|cosx|+ln|sinx|+Cf(x)=[ln(sinx)]'=cotx∫cosxf'(x)dx=∫cosxdf(x)=cosxf(x)+∫f(x)sinxdx(分部积分法)=cosxf(x)+∫cosxdx=cosxcotx+si...