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