f(x)=√2(2x/3+π/4)
T=2π/（2/3）=3π
所以最短距离=T/2
选Cf(x)=√2(2x/3+π/4)这怎么化来的？sinx+cosx =√2(√2/2*sinx+√2/2cosx) =√2(sinxcosπ/4+cosxsinπ/4) =√2sin(x+π/4)=√2(sinxcosπ/4+cosxsinπ/4)这一步又是怎么来的？sorry，反应有点慢cosπ/4 sinπ/4=√2sin(x+π/4)这是怎么从上一步化来的？详细点嘛和角公式 别追问了