And to say it has zeros means
And then, we are to derive a formula for
So, using the Remainder Theorem, are factors of .
Since there are of these factors, and is a polynomial of degree , this means that we can write as:
(This is what the expression means.)
Now the coefficient of is . So . And the coefficient of in the expansion of is which is . So:
So how do we find ?
Replace by :
which has zeros at
and, using the same method as before, the sum of the roots of this polynomial is