Question

Sa se calculeze suma:
S=1+2+4+8+16+...+256

Answer 1

 

$\displaystyle\\\text{Folosim formula:}\\\\2^0+2^1+2^2+2^3+...+2^n=2^{n+1}-1\\\\S=1+2+4+8+16+...+256=\\=2^0+2^1+2^2+2^3+...+2^8=\boxed{2^9-1}\\\\2^9-1=512-1=\boxed{511}$