证明:
当n=1时x^(2n-1)+y^(2n-1)=x+y,显然成立
假设当n=k时命题成立,即x^(2k-1)+y^(2k-1)=(x+y)*f(x)
则当n=k+1时
x^(2k+1)+y^(2k+1)
=x^2*x^(2k-1)+y^2*y^(2k-1)
=x^2*((x+y)f(x)-y^(2k-1))+y^2*y^(2k-1)
=x^2(x+y)f(x)+(y^2-x^2)y^(2k-1)
=x^2(x+y)f(x)-(x+y)(x-y)y^(2k-1)
=(x+y)*(x^2f(x)-(x-y)y^(2k-1))
所以命题成立