已知cos(-100°)=k,则tan80°=?

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已知cos(-100°)=k,则tan80°=?
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已知cos(-100°)=k,则tan80°=?
已知cos(-100°)=k,则tan80°=?

已知cos(-100°)=k,则tan80°=?
cos(-100°)=k
cos100°=k
cos(180°-80°)=k
-cos80°=k
cos80°=-k
tan80°=√(1-(cos80°)^2)/cos80°=√(1-k^2)/(-k)=-√(1-k^2)/k

∵cos(-100°)=cos100°=cos(180°-80°)=-cos80°=k, ∴cos80°=-k.∴sin80°2 21 ( ) 1k k    . ∴tan80°21sin80cos80kk  .