is a polynomial function of degree 2017 that satisfies the above functional equation for all .
Let be the sum of the distinct real roots of and be the sum of the distinct non-real roots of .
If the value of can be expressed in the form , for coprime positive integers , find .
Clarification: For any complex number where and are real, is considered real for and non-real for .
This section requires Javascript.
You are seeing this because something didn't load right. We suggest you, (a) try
refreshing the page, (b) enabling javascript if it is disabled on your browser and,
finally, (c)
loading the
non-javascript version of this page
. We're sorry about the hassle.
Let f ( x ) = g ( x ) + h ( x ) , where g ( x ) contains only the odd powers of x in f ( x ) and h ( x ) contains only the even powers of x in f ( x ) . ⇒ f ( − x ) = − g ( x ) + h ( x ) .
Plugging this into the functional equation:
g ( x ) + 4 0 3 3 h ( x ) = 4 0 3 3 ( 1 + x + x 2 + x 3 + . . . + x 2 0 1 6 + x 2 0 1 7 )
We can now assign the even/odd powers of x to g ( x ) and h ( x ) based on their definitions:
h ( x ) = 1 + x 2 + x 4 + x 6 + . . . + x 2 0 1 4 + x 2 0 1 6 g ( x ) = 4 0 3 3 ( x + x 3 + x 5 + . . . + x 2 0 1 5 + x 2 0 1 7 )
Solving for f ( x ) :
f ( x ) = ( 4 0 3 3 x + 1 ) ( 1 + x 2 + x 4 + x 6 + . . . + x 2 0 1 4 + x 2 0 1 6 ) f ( x ) = 4 0 3 3 ( x + x 3 + x 5 + . . . + x 2 0 1 5 + x 2 0 1 7 ) + 1 + x 2 + x 4 + x 6 + . . . + x 2 0 1 4 + x 2 0 1 6
We now have f ( x ) in the form f ( x ) = i ( x ) j ( x ) where i ( x ) = 4 0 3 3 x + 1 and j ( x ) = 1 + x 2 + x 4 + x 6 + . . . + x 2 0 1 4 + x 2 0 1 6
i ( x ) → x = − 4 0 3 3 1 is a root.
j ( x ) → j ( x ) ( 1 − x 2 ) = 1 − x 2 0 1 8 so the roots of j ( x ) are the 2 0 1 8 t h roots of unity excluding 1 and − 1 , all of which are non-real, distinct, and sum to 0 by Vieta's Formula .
⇒ C = 0 , R = − 4 0 3 3 1 ⇒ C − R = 4 0 3 3 1 ⇒ p + q = 4 0 3 4