Question

Sa se arate ca:

$1^{3}+ 3^{3}+ 5^{3}+...+ (2n-1)^{3} \ \textless \ 2n^{4}, n$ ∈ N si

$1+ \frac{1}{3}+ \frac{1}{7} +... + \frac{1}{(3n-2)(3n+1)} \ \textless \ \frac{n+1}{3n+1}$, n ∈ N

Answer 1

Răspuns:

Explicație pas cu pas: