关于arctanx的精选

1/1+x²arctanx的导数是1/1+x²，设y=arctanx,则x=tany，因为arctanx′=1／tany′，且tany′=(siny/cosy)′=cosycosy-siny(-siny)/cos²y=1/cos²y，则arctanx′=cos²y=cos&sup...