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幼苗
共回答了21个问题采纳率:100% 举报
原式=(2sin50°+sin10°+√3sin10°tan10°)√[1-(1-2sin^2 80°)] ={2sin50°+[1+(√3)(sin10°/cos10°)]sin10°}√(2sin^2 80°)
=[2sin50°+(cos10°+√3sin10°)sin10°/cos10°]√(2sin^2 80°)
=[2sin50°+(2cos50°sin10°/cos10°)]√(2sin^2 80°)
=2[(cos10°sin50°+cos50°sin10°)/cos10]√(2sin^2 80°)
=2(sin60°/cos10°)√(2sin^2 80°)
=2(sin60°/sin80°)√2sin 80° =2√2sin60° =√6
1年前
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