对称轴方程：2x-π/4=kπ==>x=kπ/2+π/8(k∈Z)
对称中心：2x-π/4=kπ+π/2==>x=kπ/2+3π/8 (k∈Z)
单调增区间：2kπ-π<=2x-π/4<=2kπ==>kπ-3π/8<=x<=kπ+π/8(k∈Z)
单调减区间：2kπ<=2x-π/4<=2kπ+π/2==>kπ+π/8<=x<=kπ+5π/8(k∈Z)