问题
填空题
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答案
解
=sin10°+cos70° sin80°+cos20°
=sin10°+sin20° cos10°+cos20°
=tan15°2sin15°cos5° 2cos15°cos5°
=tan
=30° 2
=2-1-cos30° sin30° 3
故答案为：2-3
搜题请搜索小程序“爱下问搜题”
|
解
=sin10°+cos70° sin80°+cos20°
=sin10°+sin20° cos10°+cos20°
=tan15°2sin15°cos5° 2cos15°cos5°
=tan
=30° 2
=2-1-cos30° sin30° 3
故答案为：2-3