Question

1+3+5+7+....501 repede pls

Answer 1

1 + 3 + 5 + 7 + ........ + 501 = 63 001

→ stabilesc cati termeni are suma cu ratia 2

( 501 - 1 ) : 2 + 1 = 500 : 2 + 1 = 251 termeni are suma

→ aplic formula sumei lui Gauss

= 251 × ( 1 + 501 ) / 2 =

= 251 × 502 / 2 =

= 251 × 251 =

= 63 001

Answer 2

1+3+5+7+...+501=
(1+2+3+4+5+...+502)-(2+4+6+...+502)=
(502*503/2)-(2(1+2+3+..+251))=
(252506/2)-(2* (251*252/2))=
126253-251*252=
126253-63252=
=63001
Succes!