A function F(x) satisfies the functional equation x2Fx+F1-x=2x-x4 for all real x. F(x) must be
x2
1-x2
1+x2
x2+x+1
x2Fx+F1-x=2x-x4 1Replacing x by 1-x, we get 1-x2F1-x+Fx=21-x-1-x4 2
Eliminating Eliminating F(1 -x) from (1) and (2), we get Fx=1-x2