Question

1+3+5+...+225= va rog repede​

Answer 1

Răspuns: $\mathrm{\boxed{S = 12~769}}$

Explicație pas cu pas:

$\mathrm{Numarul ~termenilor = (225-1):2+1}$

$\mathrm{Numarul ~termenilor = 224:2+1}$

$\mathrm{\boxed{Numarul ~termenilor = 113}}$

$\mathrm{S = 1+3+5+...+225}$

$\mathrm{S = (1+225)\cdot 113 : 2}$

$\mathrm{S = 226\cdot 113 : 2}$

$\mathrm{S = 113\cdot 113 }$

$\mathrm{S = 113^{2}}$

$\mathrm{\boxed{S = 12~769}}$