小龙王爷
幼苗
共回答了17个问题采纳率:88.2% 举报
原式=[ 2sin50°+sin10°(1+√3·tan10°)]√2cos10°
=2√2sin50°cos10°+√2 sin10°cos10°+√6 sin^210°
=2√2sin50°cos10°+√2/2 sin20°+√6/2(1-cos20°)
=2√2sin50°cos10°+√2/2 sin20°-√6/2cos20°+√6/2
=2√2sin50°cos10°-√2(√3/2cos20°-1/2sin20°)+√6/2
=2√2sin50°cos10°-√2sin(60°-20°)+√6/2
=2√2sin50°cos10°-√2sin40°+√6/2
=2√2sin50°cos10°-√2sin(50°-10°)+√6/2
=2√2sin50°cos10°-√2sin50°cos10°+√2cos50°sin10°+√6/2
=√2sin50°cos10°+√2cos50°sin10°+√6/2
=√2sin60°+√6/2
=√6
1年前
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小龙王爷
sin80=sin(90-10)=cos10 √sin^2(80)=cos10