求证1/sinA+1/cosA=sinA(1+tanA)+cosA(1+1/tanA)

来源:学生作业帮助网 编辑:作业帮 时间:2024/12/02 19:19:58
求证1/sinA+1/cosA=sinA(1+tanA)+cosA(1+1/tanA)
xM FS$ @9MFWn /ez ;AlEu5 l}|ܴʧVsN+ $wB+pQ?;*yIӜ6 @pEewUv8B en0y>BBr1-

求证1/sinA+1/cosA=sinA(1+tanA)+cosA(1+1/tanA)
求证1/sinA+1/cosA=sinA(1+tanA)+cosA(1+1/tanA)

求证1/sinA+1/cosA=sinA(1+tanA)+cosA(1+1/tanA)
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