Exercise 5.22

Use the Jacobi symbol to determine ( 113 ∕ 997 ) , ( 215 ∕ 761 ) , ( 514 ∕ 1093 ) , and ( 401 ∕ 757 ) .

Answers

Proof. ( 113 ∕ 997 ) = ( 997 ∕ 113 ) = ( 93 ∕ 113 ) = ( 113 ∕ 93 ) = ( 20 ∕ 93 ) = ( 2 2 ∕ 93 ) ( 5 ∕ 93 ) = ( 5 ∕ 93 ) = ( 93 ∕ 5 ) = ( 3 ∕ 5 ) = ( 5 ∕ 3 ) = ( 2 ∕ 3 ) = − 1 .

( 215 ∕ 761 ) = ( 761 ∕ 215 ) = ( 116 ∕ 215 ) = ( 2 2 ∕ 215 ) ( 29 ∕ 215 ) = ( 29 ∕ 215 ) = ( 215 ∕ 29 ) = ( 12 ∕ 29 ) = ( 2 2 ∕ 29 ) ( 3 ∕ 29 ) = ( 3 ∕ 29 ) = ( 29 ∕ 3 ) = ( 2 ∕ 3 ) = − 1 .

( 514 ∕ 1093 ) = ( 2 ∕ 1093 ) ( 257 ∕ 1093 ) = − ( 257 ∕ 1093 ) = − ( 1093 ∕ 257 ) = − ( 65 ∕ 257 ) = − ( 257 ∕ 65 ) = − ( 62 ∕ 65 ) = − ( 2 ∕ 65 ) ( 31 ∕ 65 ) = − ( 31 ∕ 65 ) = − ( 65 ∕ 31 ) = − ( 3 ∕ 31 ) = ( 31 ∕ 3 ) = ( 1 ∕ 3 ) = 1 .

( 401 ∕ 757 ) = ( 757 ∕ 401 ) = ( 356 ∕ 401 ) = ( 401 ∕ 89 ) = ( 45 ∕ 89 ) = ( 89 ∕ 45 ) = ( 44 ∕ 45 ) = ( 2 2 ∕ 45 ) ( 11 ∕ 45 ) = ( 11 ∕ 45 ) = ( 45 ∕ 11 ) = ( 1 ∕ 11 ) = 1 . □

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2022-07-19 00:00
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