请问是cos2x还是(cosx)^2?要是cos2x,∫dx/cos2x=0.5×∫d(2x)/cos2x=0.5×∫dt/cost=0.5×∫costdt/(cost)^2=0.5×∫d(sint)/1-sint^2,相信从这儿开始楼主就会了.要是(cosx)^2,∫dx/(cosx)^2=tanx+C.希望你满意....