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Laurandy
a fost răspuns

S (n)=8n^2 -6n
Aflati a1,r,a2016

Răspuns :

Renatemambouko
 Sn=8*n^2-6*n
 S(1)=8*1^2-6*1=8-6=2
 S(2)=8*2^2-6*2=32-12=20
       
S(1)=a₁ =2
S(2) -S(1) =a₁+a₂ -a₁ =a₂ =20-2 =18
a₂=a₁+r  
18=2+r
 r=16

a₂₀₁₆ =2+(2016-1)×16)=2+32240=32242
Vaduvadenisadr
a(n)= S(n)-S(n-1)
an=8n^2-6n-[8(n-1)^2-6(n-1)]
an=8n^2-6n-[8(n^2-2n+1)-6n+6]
an=8n^2-6n-8n^2+16n-8+6n-6
an=16n-14
r=a(n+1)-a(n)
r=16(n+1)-14-16n+14
r=16
a(1)=16-14=2
a(2016)=a(1)+2015x16=32242

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