求值 sin10°分之一-sin80°分之根号3

原式=1−2sin10°cos10°cos10°−1−cos2170°=sin210°−2sin10°cos10°+cos210°cos10°−sin2170°=|sin10°−cos10°|cos1

原式=(1-cos20°)/2+(1+cos80°)/2+sin10°cos40°(利用二倍角公式)=1+(cos80°-cos20°)/2+[sin(10°+40°)+sin(10°-40°)]/2

SIN10°SIN30°SIN50°SIN70°SIN90°=(1/2)*SIN10°SIN50°SIN70°=(1/4)*2COS10°SIN10°SIN50°SIN70°/COS10°=(1/4)

1/sin10°-√3/sin80°=1/sin10-√3/cos10=(cos10-√3sin10)/sin10cos10=2(1/2cos10-√3/2*sin10)/sin10cos10=2co

原式=2tan70°[cos10°*1/2+（√3/2）sin10°]-2cos40°=2tan70°(cos10°sin30°+cos30°sin10°)-2cos40°=2tan70°sin40°

1−2sin10°cos10°sin10°−1−sin210°=|sin10°−cos10°|sin10°−cos10°=cos10°−sin10°sin10°−cos10°=-1故答案为：-1

根号（1-2sin10cos10）/cos10-根号(1-sin^2100)=根号[(cos10-sin10)^2]/[cos10-根号(cos100)^2]=(cos10-sin10)/[cos10

(sin10°+sin20°)/(cos10°+cos20°)（和差化积得到下式）=2sin15°cos5°/(2cos15°cos5°)=tan15°=tan(45°-30°)=(1-tan30°)

sin50=sin(60-10)=√3/2cos10-1/2*sin10所以原式=(sin10)^2+(√3/2cos10-1/2*sin10)^2+(sin10)*(√3/2cos10-1/2*si

换成cos变成：cos80＊cos40＊cos20乘上sin20,倍角公式,变成sin160／（sin20＊8）＝1／8

sin10°sin50°sin70°=1/2(2cos10°sin10°sin50°sin70°）/cos10°=1/2(sin20°cos20°sin50°）/cos10°=1/4(sin40°co

题目错了吧sin80应该是sin30sin10sin30sin50sin70=cos10sin10sin30sin50sin70/cos10=1/2sin20sin70sin30sin50/cos10

sin10°*sin50°*sin70°=0.17*0.77*0.94=0.12

sin10°+sin50°-sin70°=sin(20°+30°)+sin10°-sin70°=√3/2*sin20°+1/2*cos20°-cos20°+sin10°=√3/2*sin20°-1/2

1-sin²10=cos²10所以原式=(2sin50+sin10+√3sin10*sin10/cos10)*cos10=2sin50cos10+sin10cos10+√3sin&

1.求值sin50°（1+√3tan10°）=sin50(1+√3sin10/cos10)=2sin50(sin30cos10+cos30sin10)/cos10=2sin50sin40/cos10=

分子＝根号下(Cos10º-Sin10º)²分母＝Sin10º－Cos10º所以比值为－1

[2sin50°+sin10°(1+√3tan10°)]√(2sin80°)=[2sin50+sin10(cos10+√3sin10)/cos10]√2sin80=[2sin50cos10+2sin1

原式=1/sin10°-√3/cos10°=(cos10°-√3sin10°)/(sin10°cos10°)=4[(1/2)cos10°-(√3/2)sin10°]/(2sin10°cos10°)=4

cos10°/tan20°+√3sin10°tan70°-2cos40°=cos10°/tan20°+√3sin10°/tan20°-2cos40°=2(1/2cos10°+√3/2sin10°)/t