1,2x+ π/6属于【2kπ-π/2,2kπ+π/2】,x∈[kπ-π/3,kπ+π/6]为增区间,x属于【kπ+π/6,kπ+2π/3】是减区间,以上k都属于整数
2,f(x)最大2+a+1=4,a=1
3,2x+π/6=2kπ+π/2,x=kπ+π/6