Question

Calculați
( 2+4+6 +. ........+2004 ) =
( 5+10 + 15 +. .....+ 550 ) =
( 3 + 6 + 9 +. .....+ 1200 ) =

Answer 1

Răspuns:

2(1+2+3+...+1002)=2(1002•1003)/2=1005006

5(1+2+3+...+110)=5(110•111)/2=30525

3(1+2+3+...+400)=3(400•401)/2=240600