1）y'=1+2sinx=0, 得：sinx=-1/2, x=2kπ-π/6, 或x=(2k+1)π+π/6x=2kπ-π/6时,y=(2kπ-π/6)-√3, 为极小值x=(2k+1)π+π/6时,y=(2k+1)π+π/6+√3,为极大值2）y'=-8x/(x^2+3)^2=0 ,得：x=0y(0)=4/3, 此为极大值3...单调区间1）y'=cosx+sinx你写错了吧应该是y'=cosx-sinxsinx的导数为cosxcosx的导数为-sinx,