设cos80°=k,则tan100°=_.
问题描述:
设cos80°=k,则tan100°=___.
答
∵cos80°=k,∴sin80°=
,则tan100°=-tan80°=-
1-k2
=-sin80° cos80°
,
1-k2
k
故答案为:-
.
1-k2
k