帮帮哦,原题是这样的:sin(540-x)/tan(900-x) 乘以 1/tan(450-x)tan(810-x) 乘以 cos(360-x)/sin(-x)条件是tanx=2我怎么化简都是得sinx,真是邪门了,
来源:学生作业帮助网 编辑:作业帮 时间:2024/11/16 15:51:09
帮帮哦,原题是这样的:sin(540-x)/tan(900-x) 乘以 1/tan(450-x)tan(810-x) 乘以 cos(360-x)/sin(-x)条件是tanx=2我怎么化简都是得sinx,真是邪门了,
帮帮哦,原题是这样的:
sin(540-x)/tan(900-x) 乘以 1/tan(450-x)tan(810-x) 乘以 cos(360-x)/sin(-x)
条件是tanx=2
我怎么化简都是得sinx,真是邪门了,
帮帮哦,原题是这样的:sin(540-x)/tan(900-x) 乘以 1/tan(450-x)tan(810-x) 乘以 cos(360-x)/sin(-x)条件是tanx=2我怎么化简都是得sinx,真是邪门了,
原式是这样吧?
sin(540-x)/tan(900-x) *1/(tan(450-x)tan(810-x) ) *cos(360-x)/sin(-x)
sin(540-x)=sin(180-x)=sinx
tan(900-x)=tan(-x)=-tanx
tan(450-x)=tan(90-x)=cotx
tan(810-x)=tan(90-x)=cotx
cos(360-x)=cos(-x)=cosx
sin(-x)=-sinx
所以原式=sinx/(-tanx)*1/(cotx*cotx)*cosx/(-sinx)
=sinx*cosx/sinx*sinx/cosx*sinx/cosx*cosx/sinx
=sinx
就是sinx
tanx=2
sinx=±(2√5)/5
原式=[sin(180°-x)/tan(180°-x)][tan(90°-x)/tan(90°-x)][cos(-x)/sin(-x)]=sin(180°-x)cos(-x)/sin(-x)=[-sin(-x)]/sin(-x)]cos(-x)=-cos(-x)