Unformatted text preview: C ( x ) at the four 4th roots. (iii) Create the polynomial D ( x ) = C (1) + C ( i ) x + C (1) x 2 + C (i ) x 3 . (iv) Evaluate D at the four 4th roots of unity 1, i ,1,i . (v) Use these values to construct C ( x ). Problem 2. Use the FFT algorithm to evaluate f ( x ) = 84 x + 2 x 2 + 3 x 35 x 44 x 5 + 2 x 6 + x 7 at the eight 8th roots of unity mod 17. You may stop using recursion when evaluating a linear function ( a + bx ), which is easier to do directly. The eight 8th roots of unity mod 17 are 1, 2, 4, 8, 16, 15, 13, 9; it is easier to calculate with 1, 2, 4, 8, 1, 2, 4, 8. Do this by hand, and show your work....
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 Fall '08
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 Clyde Kruskal

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