Question

Cine mă poate ajuta cu exercițiul ăsta ? Va rog !
200+199-198+197+196-195+...+5+4-3+2+1-0

Answer 1

200+1+197+1 +194+1+191+1+.....+8+1+5+1+2+1=

1+2+1+5+1......+191+1+194+1+197+1+200=
 (1+3*0+2)+ (1+3*1+2)+....+(1+3*63) +(1+3*64+2) +(1+3*65+2)+(1+3*66+2)=

(3*0+3*1+3*3+...3*66) +(2+2+...2) [67 de 2]+(1+1+...+1)[67de 1]=

3 (1+2+...+66) +2*67 +67=

3*66*67/2+3*67=
3*67*33 +3*67=
3*67(33+1)=
3*67*34=6633, cerinta