y=√2cos2x向上平移2个单位：y-2 = √2cos2x,再向右平移π/8单位：y-2 = √2cos[2(x - π/8)]
即得到f(x) = 2 + √2cos[2(x - π/8)]
它的最小正周期 = 2π/2 = π,∴对称轴为x = kπ + (π/8),k为任意整数
同时对称中心为：((π/8) + (kπ/2) ,2),k为任意整数
单调递增区间为：[kπ - (3π/8) ,kπ + (π/8)],k为任意整数
当f(x) = 2 + √2/2时,cos2x = 1/2,∴x = {x l x = kπ + (π/6),k∈Z}