👤
a fost răspuns

1) Calculați suma
1/1*2+1/2*3+...+1/31*32 .

Răspuns :

AlyBudai2006
1/(1×2) = 1/1 - 1/2   
1/(2×3) = 1/2 - 1/3
1/(3×4) = 1/3 - 1/4
..................................
1/(31×32)= 1/31 - 1/32  
______________________
S= 1/1-1/2+1/3-1/3+1/3-1/4+... +1/31-1/32 = 1/1 - 1/32 = (32-1)/32 = 31/32

Alte intrebari