根号(1-2sin40°cos40°)/ (cos40°-根号1-sin^2 50°)

求值。谢谢~

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根号镇樱歼(1-2sin40°cos40°)/ (cos40°-根号1-sin^2 50°)
=根号(sin²颂高40°+cos²40°-2sin40°cos40°)/(cos40°-cos50°)
=(cos40°-sin40°)/御冲(cos40°-sin40°)
=1

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