f(x)=x^(-n^2+2n+3)
=x^[(-n+3)(n+ 1)]
N=2k is an even number.
(-n+3)(n+ 1) is an odd number.
f(-x)=(-x)^(-n^2+2n+3)=-x^(-n^2+2n+3)=-f(x)
F(x) is odd function.
F(x) monotonically increases on r.
x^2-x>; x+3
x^2-2x-3>; 0
(x-3)(x+ 1)>0
x & lt- 1x & gt; three