Question

calculati 11+12+13+...+52 URGENT!! DAU COROANA!!!​

Answer 1

 

$\displaystyle\bf\\Calculati: \\\\11+12+13+...+52\\\\Rezolvare:\\\\Pasul~1: Calculam~numarul~de~termeni~(n).\\\\n=52-11+1=41+1=42~de~termeni\\\\Pasul~2:Aplicam~formula~lui~Gauss.\\\\S=\frac{n(52+11)}{2}=\frac{42\times63}{2}=21\times63=\boxed{\bf1323}$

 

 

Answer 2

11+12+13+...+52

=(1+2+3+...+52)-(1+2+...+10)

=[52*(52+1)]/2-[10*(10+1)]/2

=(52*53)/2-(10*11)/2

=26*53-5*11

=1378-55

=1323

suma lui Gauss: [n(n+1)]/2

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