Question

Calculand 1 supra n -1 supra n+1 obtinem:

Answer 1

Răspuns:

1/n - 1/(n+1)=aducere la acelasi numitor=

1/[n(n+1)]

Answer 2

$\displaystyle ^{^{^{^{\displaystyle n+1)}}}}\frac{1}{n} - ^{^{^{^{\displaystyle n)}}}}\!\!\!\frac{1}{n+1} =\frac{n+1}{n(n+1)}-\frac{n}{n(n+1)} = \frac{(n+1)-n}{n(n+1)}=\boxed{\displaystyle \frac{1}{n(n+1)}}$