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Arata ca b= 1+3+5+...+2011 este patrat perfect. Urgent va rooog . Mersi

Răspuns :

1+3+5+...(2n-1)=n^2
1+3+..+2011
2n-1=2011
2n=2012
n= 2012/2 = 1006
=> 1+3+5+...2011=1006^2 patrat perfect
suma de 1006 numere impare 
b= ( 1 + 2011 ) · 1006 /2 = 2012 ·503 = 4·503·503 = 2² ·503² =( 2· 503 )² = 1006²