MathDB
Turkey NMO 2008 1st Round - P03 (Algebra)

Source:

August 24, 2012
algebrapolynomial

Problem Statement

Let P(x)=1x+x2x3++x18x19P(x) = 1-x+x^2-x^3+\dots+x^{18}-x^{19} and Q(x)=P(x1)Q(x)=P(x-1). What is the coefficient of x2x^2 in polynomial QQ?
<spanclass=latexbold>(A)</span> 840<spanclass=latexbold>(B)</span> 816<spanclass=latexbold>(C)</span> 969<spanclass=latexbold>(D)</span> 1020<spanclass=latexbold>(E)</span> 1140 <span class='latex-bold'>(A)</span>\ 840 \qquad<span class='latex-bold'>(B)</span>\ 816 \qquad<span class='latex-bold'>(C)</span>\ 969 \qquad<span class='latex-bold'>(D)</span>\ 1020 \qquad<span class='latex-bold'>(E)</span>\ 1140