f(x) = sin2x-2√3cos平方x+√3+a= sin2x-√3cos2x+a= 2sin(2x-π/6)+a2x-π/6属于(2kπ+π/2,2kπ+3π/2)时单调减∴单调减区间:x属于((kπ+π/3,kπ+5π/6)x∈[0,π/2]2x∈[0,π]2x-π/6∈[-π/6,5π/6]2x-π/6=-π/6时,最小值 = 2*(-1/2)+a=-1+a=-2a=-12x-π/6=π/2时,最大值 = 2*1-1= 1