2008-11-19 22:52sin10°sin(-260°)-cos100°cos(-170°)-tan190°tan280°=sin10sin(-180-80)-cos(90+10)cos(-180+10)-tan(180+10)tan(270+10)
=sin10sin80-sin10cos10+tan10cot10
=sin10cos10-sin10cos10+1
=1
如追加其它问题,
2008-11-19 22:52sin10°sin(-260°)-cos100°cos(-170°)-tan190°tan280°=sin10sin(-180-80)-cos(90+10)cos(-180+10)-tan(180+10)tan(270+10)
=sin10sin80-sin10cos10+tan10cot10
=sin10cos10-sin10cos10+1
=1
如追加其它问题,