yuexinyi
幼苗
共回答了13个问题采纳率:92.3% 举报
tanx+cotx
=sinx/cosx +cosx/sinx
=[(sinx)^2+(cosx)^2]/sinxcosx
=1/(sinxcosx)
1+tan^2(x)
=1+sin^2(x)/cos^2(x)
=cos^2(x)/cos^2(x)+sin^2(x)/cos^2(x)
=[sin^2(x)+cos^2(x)]/cos^2(x)
=1/cos^2(x)
1+cot^2(x)
=1+cos^2(x)/sin^2(x)
=sin^2(x)/sin^2(x)+cos^2(x)/sin^2(x)
=[sin^2(x)+cos^2(x)]/sin^2(x)
=1/sin^2(x)
tanxcotx
=[sinx/cosx]*[cosx/sinx]
=1
1年前
1