Question

Arătați că următoarele numere sunt pătrate perfecte A1 plus 3 plus 5 plus 7 plus 9 plus 11 b 1 plus 3 plus 5 plus 7 plus puncte puncte plus 19​

Answer 1

Răspuns:

a) 1+3+5+7+9+11=36=6²→pp

b) 1+3+5+7+...+19=1+19+3+17+5+15+7+13+9+11=20+20+20+20+20=100=10²→pp

Answer 2

a)

$1+3+5+7+9+11=\\(1+9)+(3+7)+(5+11)=\\10+10+16=\\=36=6^{2}$

b)

$1+3+5+7+...+19=\\36+13+15+17+19=\\(36+15+19)+(13+17)=\\70+30=100\\=10^{2}$