Question

Fie S = $\frac{1}{12} + \frac{1}{13} + ... + \frac{1}{35}$.
a) Cati termeni are suma ?
b) Aratati ca S<2

Answer 1

a)35-12+1=24 termeni
b)Prin minorarea numitorului fiecarei fractii avem:
S<1/12+1/12+...+1/12=24·1/12=2