问题
填空题
计算
|
答案
1+
tan10°=1+3 3
=sin10° cos10°
=cos10°+
sin10°3 cos10°
=2sin(10°+30°) cos10°
，2sin40° cos10°
∴原式=
?sin80° cos50°
=2sin40° cos10°
?cos10° sin40°
=2．2sin40° cos10°
故答案为2
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