(sinx-cosx,tanx)在第一象限所以sinx-cosx＞0,即√2sin(x-π/4)＞0得0+2kπ＜ x-π/4＜π+2kπ所以π/4+2kπ＜x＜5π/4+2kπ因为x∈[0,2π),所以 π/4＜x＜5π/4又有tanx＞0,得0＜x＜π/2 or π＜x＜3π/2所以综合可...