Solve this:

Solve this: ... an _ are the nth roots of unity, then prove

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-11+12-α1+12-α2+.....+12-αn-1=n2n-12n-112-α1+12-α2+.....+12-αn-1=n2n-12n-1-112-α1+12-α2+.....+12-αn-1=(n×2n×2-1)-(2n-1)2n-112-α1+12-α2+.....+12-αn-1=(n×2n×2-1)-2n+12n-112-α1+12-α2+.....+12-αn-1=2n((n×2-1)-1)+12n-112-α1+12-α2+.....+12-αn-1=2n(n2-1)+12n-112-α1+12-α2+.....+12-αn-1=2n2(n-2)+12n-112-α1+12-α2+.....+12-αn-1=(n-2)2n-1+12n-1; Hence ProvedRegards.

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