原式等于：2（根号3倍/2 sin2x+1/2cos2x）=2sin(2x+π/6);sin 函数的单调减区间是{2Kπ+π/2,2Kπ+3π/2}；所以：2Kπ+π/2 ＜2X+π/6＜2Kπ+3π/2：2Kπ+π/3＜2X＜2Kπ+4π/3：kπ+π/6＜x＜kπ+2π/3；所以单调区...