Răspuns :
1 + 3 + 5 + 7 + 9 + ....... + 57 = 841
→ stabilesc cati termeni are suma cu ratia 2
( 57 - 1 ) : 2 + 1 = 56 : 2 + 1 = 28 + 1 = 29 termeni are suma
→ aplic formula sumei lui Gauss:
= 29 × ( 1 + 57 ) : 2 =
= 29 × 58 : 2 =
= 841
1 + 3 + 5 + 7 + 9 + ....... + 57 = 841
→ stabilesc cati termeni are suma cu ratia 2
( 57 - 1 ) : 2 + 1 = 56 : 2 + 1 = 28 + 1 = 29 termeni are suma
→ aplic formula sumei lui Gauss:
= 29 × ( 1 + 57 ) : 2 =
= 29 × 58 : 2 =
= 841