Question

Arata ca urmatoarele numere sunt patratele unor numere naturale:
a)1+3+5
b)1+3+5+7+9
c)1+3+5+7+9+11+13
d)1+3+5+...+99

Nu am nici o idee.....

Answer 1

a)1+3+5=9
9=3 la puterea a doua (patrat perfect)
b)1+3+5+7+9=25
25=5 la puterea a doua
c)1+3+5+7+9+11+13=49
49=7 la puterea a doua
d)1+3+5+...+99=
(100x50):2=2500
2500=50 la puterea a doua

Answer 2

a)1+3+5=9=3^2-pătrat perfect
b)1+3+5+7+9=25=5^2-pătrat perfect
c)1+3+5+7+9+11+13=49=7^2-pătrat perfect
d)1+3+5+...+99=(100•50):2=2500=50^2-pătrat perfect