Question

Va rog repede

Dau coroana

Answer 1

1) 2(1+2+3+...+50)=2×50×51:2=50×51=2550

2) 1+2+3+4+...+101=101×102:2=10302:2=5151

2¹+2²+2³+....+2¹⁰¹=2⁵¹⁵¹

3)U(1991²⁰)=U(1)

U(1993²⁰)=U(1)

U(1995²⁰)=U(5)

1+1+5=7 => 1991²⁰+1993²⁰+1995²⁰nu este patrat perfect

deoare ce patratele perfecte se termina in 0,1,4,9,6,5.

Sper ca te-am ajutat.