Gasiti n

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Beniamin Bogosel
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Gasiti n

Post by Beniamin Bogosel »

Gasiti numerele naturale \( n \) pentru care \( 8n+1,\ 24n+1 \) sunt patrate perfecte si \( 8n+3 \) e prim.
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Sabin Salajan
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Post by Sabin Salajan »

Ideea problemei este de a scrie numarul prim \( 8n+3 \) sub forma \( x^2-y^2 \)

Avem \( 4(8n+1)-24n+1=8n+3 \)

Notand \( 8n+1 \) cu \( a^2 \) si \( 24n+1 \) cu \( b^2 \)

=> \( (2a-b)(2a+b)=8n+3 \) => \( 2a-b=1 \) <=> \( 32n+4=24n+1+1+2b \) <=> \( 4n+1=b \) <=> \( 16n^2+8n+1=24n+1 \) de unde

\( n=0 \) si \( n=1 \) sunt solutii,care verifica si ipoteza
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