sin164sin224+sin254sin314化简这道题应该要怎么做,如题

sin164sin224+sin254sin314化简这道题应该要怎么做,如题
sin164sin224+sin254sin314化简这道题应该要怎么做,
如题

sin164sin224+sin254sin314化简这道题应该要怎么做,如题
sin164°sin224°+sin254°sin314°
=sin16°(-sin44°)+(-sin74°)(-sin46°)
=sin74°sin46°-sin16°sin44°
=sin74°cos44°-cos74°sin44°
=sin(74°-44°)
=sin30
=1/2

一楼的放他妈的屁，我给你解~！~ sin130'（cos10+根号3sin10)/cos10 =2sin130cos50/cos10 =2sin50cos50/cos10 =sin100/cos10 =sin80/sin80

sin164sin224+sin254sin314=sin16(-sin44)+(-sin74)(-sin46)=-sin16sin44+sin74sin46=-sin16cos46+cos16sin46=cos16sin46-sin16cos46=sin(46-16)=sin30=1/2