设 cos(-80°)=k,则tan(100°)=?

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设cos(-80°)=k,则tan(100°)=?设cos(-80°)=k,则tan(100°)=?设cos(-80°)=k,则tan(100°)=?cos80°=-k=cos(180°-100°)=

设 cos(-80°)=k,则tan(100°)=?
设 cos(-80°)=k,则tan(100°)=?

设 cos(-80°)=k,则tan(100°)=?

cos80°=-k
=cos(180°-100°)
=-cos100°
∴cos100°=k
sin^2100°+cos^2100°=1
∴sin100°=√1-k^2
∴tan100°=sin100°/cos100°= k/√1-k^2
额-感觉好像错了也 怪怪的