Let x1,x2,…,x100 be real numbers such that x1+x2+⋯+x100=1 and 1−x1x1+1−x2x2+⋯+1−x100x100=1.Find 1−x1x12+1−x2x22+⋯+1−x100x1002.
Solution — click to reveal
In general, 1−xx2=1−xx2−x+x=1−xx(x−1)+x=1−xx−x,so 1−x1x12+1−x2x22+⋯+1−x100x1002=1−x1x1+1−x2x2+⋯+1−x100x100−(x1+x2+⋯+x100)=1−1=0.