根号下大于等于0，真数大于0所以sinx>=√3/2=sin(2kπ+π/3)=sin(2kπ+2π/3)所以2kπ+π/3<=x<=2kπ+2π/3√2-2cosx>0cosx<√2/2=cos(2kπ+π/4)=cos(2kπ+7π/4)所以2kπ+π/4两者取交集所以定义域[2kπ+π/3,2kπ+2π/3]
