Question

calculati:(1+2+3+...100):(-101). B)(-2-4-6-...1000):(-2) c)(-3-6-9-...3000):(1+2+3+...1000)

Answer 1

trebuie sa stii formula :1+2+3+.....+n=n(n+1)/2'deci
1+2+3+...+100=100x101/2, care impartit la (-101)=-50
b) dai factor comun pe -2, rezulta:  -2(1+2+3+....+500):(-2)=
-2x500x501/2:(-2)=250x501
c) -3(1+2+3+...+1000):1000x1001/2=-3x1000x1001/2:500x1001=
-3