1/sin10°-√3/sin80°=______ - 知识问答

1/sin10°-√3/sin80°=______________

1个回答

原式=1/sin10-√3/cos10
=(cos10-√3sin10)/sin10cos10
=2(1/2cos10-√3/2*sin10)/sin10cos10
=2cos(10+60)/sin10cos10
=4cos70/sin20
=4

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