1/cos50度+tan10度=?
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1/cos50度+tan10度=?
求值
求值
1/cos50°+tg10°=1/sin40° + sin10°/cos10°
=1/sin40° +(sin10°*2sin10°) /(cos10°*2sin10°)
=1/sin40° +2(sin10°)^2 /sin20°
=1/sin40° +(1-cos20°) /sin20°
=1/sin40°+(1-cos20°)*2cos20° /sin20°*2cos20°
=[1+2cos20°-2(cos20°)^2] /sin40°
=(2cos20°-cos40°) /sin40°
=(cos20°+2sin30°sin10°) /sin40°
=(sin70°+sin10°) /sin40°
=[sin(40°+30°)+sin(40°-30°)] /sin40°
=2sin40°cos30°/sin40°=2cos30°=√3
=1/sin40° +(sin10°*2sin10°) /(cos10°*2sin10°)
=1/sin40° +2(sin10°)^2 /sin20°
=1/sin40° +(1-cos20°) /sin20°
=1/sin40°+(1-cos20°)*2cos20° /sin20°*2cos20°
=[1+2cos20°-2(cos20°)^2] /sin40°
=(2cos20°-cos40°) /sin40°
=(cos20°+2sin30°sin10°) /sin40°
=(sin70°+sin10°) /sin40°
=[sin(40°+30°)+sin(40°-30°)] /sin40°
=2sin40°cos30°/sin40°=2cos30°=√3
求值:2sin50°+cos10°*(1+根号3tan10°)/cs35°cos40°+cos50°cos55°
化简求值2sin50°+cos10°(1+3tan10°)cos35°cos40°+cos50°cos55°
sin50度(1+根号3tan10度)=?
化简 sin50度(1+根号3tan10度) tan10度tan20度+tan20度tan60度+tan60度tan10
sin50度(1+根号3tan10度)
sin的平方20度+cos的平方50度+sin20度*cos50度=
1)求值sin^2 20度+cos^2 50度+sin20度cos50度
cos2x=-1/9,则tan平方x乘sin平方x= tan10度tan20度+根号3(tan10度+tan20度)=
sin50度(1+根号3tan10度)-cos20度/cos80度根号1-cos20度=
化简Sin50度(1+根号3tan10度)
化简:sin50度(1+根号3*tan10度)
化简:sin40度(1+根号3*tan10度)