求证,sina*(1+tana)+cosa*(1+1/tana)=1/sina+1/cosa
来源:学生作业帮助网 编辑:作业帮 时间:2024/06/13 15:24:31
![求证,sina*(1+tana)+cosa*(1+1/tana)=1/sina+1/cosa](/uploads/image/z/2497333-13-3.jpg?t=%E6%B1%82%E8%AF%81%2Csina%2A%281%2Btana%29%2Bcosa%2A%281%2B1%2Ftana%29%3D1%2Fsina%2B1%2Fcosa)
求证,sina*(1+tana)+cosa*(1+1/tana)=1/sina+1/cosa
求证,sina*(1+tana)+cosa*(1+1/tana)=1/sina+1/cosa
求证,sina*(1+tana)+cosa*(1+1/tana)=1/sina+1/cosa
sina*(1+tana)+cosa*(1+1/tana)=1/sina+1/cosa
=sina*(1+sina/cosa)+cosa*(1+cosa/sina)
=sina+sin^2/cosa+cos^2a/sina+cosa
=sina+cosa+[(sin^3a+cos^a)/sinacosa]
=sina+cosa+[(sina+cosa)(sin^2a+cos^2a-sinacosa)/sinacosa]
=sina+cosa+[(sina+cosa)(1-sinacosa)/sinacosa]
=sina+cosa+(sina+cosa)/sinacosa-sina-cosa
=(sina+cosa)/sinacosa
=1/sina+1/cosa
那个,还是画一幅图,然后设3条边的长,慢慢对着做吧