arctanx的导数是什么

1、arctanx的导数是：1/1+x2。2、设y=arctanx,则x=tany。因为arctanx′=1／tany′，且tany′=(siny/cosy)′=cosycosy-siny(-siny)/cos2y=1/cos2y。则arctanx′=cos2y=cos2y/sin2y+cos2y=1/1+tan2y=1/1+x2。所以arctanx的导数是1/1+x2...