相邻对称轴的距离=T/2=π/2
T=π
所以w=2
偶函数则对称轴x=0
即f(0)=±1
a-π/6=kπ+π/2
a=kπ+2π/3
所以a=2π/3
所以f(π/8)=2sin(π/4+2π/3-π/6)
=2sin(3π/4)
=√2