飞虎012队
幼苗
共回答了18个问题采纳率:83.3% 举报
sina=4sin(a+B)
=>sina=4sinacosB+4cosasinB
=>sina/cosa=4sinB/(1-4cosB)=tana
tan(a+B)=sin(a+B)/cos(a+B)
=(sinacosB+cosasinB)/(cosacosB-sinasinB)
=(tanacosB+sinB)(cosB-tanasinB)
=[4sinBcosB/(1-4cosB)+sinB]/[cosB-4(sinB)^2/(1-cosB)]
=[(4sinBcosB+sinB-4sinBcosB)/(1-4cosB)]/{[cosB-4(cosB)^2-4(sinB)^2]/(1-4cosB)]}
=sinB/(cosB-4)
=负或者正根号(1-a)^2/(4-a)
1年前
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