Răspuns :
a = (x*x³*x⁵......*x¹⁹) = x⁽¹⁺³⁺ ⁺¹⁹⁾ = x²⁰⁾² = patrat perfect
1+3+..+19 = 20²
Obs. Am calculat 1+3+..19 dupa formula
1+3+..+2n-1 = 2²
a = (x*x³*x⁵......*x¹⁹) = x⁽¹⁺³⁺ ⁺¹⁹⁾ = x²⁰⁾² = patrat perfect
1+3+..+19 = 20²
Obs. Am calculat 1+3+..19 dupa formula
1+3+..+2n-1 = 2²