原式=1+2sinxcosx+4*(1+cos2x)/2=sin2x+2cos2x+3=√5sin(2x+arctan2)+3递减区间：2kπ+π/2≤2x+arctan2≤2kπ+3π/2,得x∈[kπ+π/4-1/2*arctan2,kπ+3π/4-1/2*arctan2]最大值√5+3,最小值-√5+3...