f(x)=sin(x+5π/2)
=sin(x+π/2+2π)
=sin(x+π/2)
=cosx
所以是偶函数
g(x)=cos(x+5π/2)
=cos(x+π/2+2π)
=cos(x+π/2)
=-sinx
所以是奇函数