化简：sin315°sin(-1260°)+cos570°sin(-840°)

来源：百度知道编辑：UC知道时间：2024/06/06 08:55:58

sin315°*sin(-1260°)+cos570°*sin(-840°)
=-sin45*(-sin180)+cos150(-sin120)
= sin45*sin180-cos150*sin120
=（根号2）/2*1-（-根号3）/2*（根号3）/2
=（根号2）/2+3/2
=（根号2+3）/2

sin315°sin(-1260°)+cos570°sin(-840°)
=-sin45*(-sin180)+cos150(-sin120)
=0+(-cos30)(sin60)
=-3/4

过程：
=sin（-75°）sin180°+cos110°sin(-120)
= 0 + sin20°sin120°
= sin20° * sin60°

化简:sin(-1070°)*sin99°+sin(-171°)*sin(-261°) 化简：sin^2(A-30)+sin^2(A+30)-sin^2A sin sin sin的歌词 sin(x-20°)+cos(x+70°)+sin(x+20°)sec(70-x)=？ 3sin(x+20°)+5sin(x+80°)的最大值是多少？要过程化简:(1-(sin a)^6-(cos a)^6)/(1-(sin a)^4-(cos a)^4) sin70°cos25°-sin°20cos25° =? sin^2(225°)-cos^2(157.5°)=? 根号[1-2sin(3-π)cos(3-π)]化简化简 sin(arccos1/2+arccos1/3)