Question

Am nevoie sa stiu 5​

Answer 1

a) 1-2+3-4+5-6+...+49-50

Le grupam A={1-2;3-4;5-6;...;49-50}, rezultand faptul ca toate grupele dau -1, asadar rezultatul ar fi=-1×card A

card A=card B, unde B={-2;-4;-6;...;-50}

card B=50:2+1-1=25

1-2+3-4+5-6+...+49-50=-1×25=-25

b) -1-2-3-...-49-50=

-1(1+2+3+...+49+50)=

-1(50×51:2)=

-1(25×51)

-1275