Solve this: Solve this: ... an _ are the nth roots of unity, then prove Share with your friends Share 1 Sanjay Kumar Manjhi answered this Dear Student,Prove that: 12-α1+12-α2+.....+12-αn-1=(n-2)2n-1+12n-1Now, We know that,If 1, α1,α2,.......αn are nth root of unity, then;1x-1+1x-α+1x-α2+.....+1x-αn-1=nxn-1xn-1Now put x=2, we get;⇒12-1+12-α1+12-α2+.....+12-αn-1=n2n-12n-1⇒1+12-α1+12-α2+.....+12-αn-1=n2n-12n-1⇒12-α1+12-α2+.....+12-αn-1=n2n-12n-1-1⇒12-α1+12-α2+.....+12-αn-1=(n×2n×2-1)-(2n-1)2n-1⇒12-α1+12-α2+.....+12-αn-1=(n×2n×2-1)-2n+12n-1⇒12-α1+12-α2+.....+12-αn-1=2n((n×2-1)-1)+12n-1⇒12-α1+12-α2+.....+12-αn-1=2n(n2-1)+12n-1⇒12-α1+12-α2+.....+12-αn-1=2n2(n-2)+12n-1⇒12-α1+12-α2+.....+12-αn-1=(n-2)2n-1+12n-1; Hence ProvedRegards. 2 View Full Answer