Question

a) Arătați ca 1/n-1/n+k=k/n(n+k) oricare ar fi n,k € N stelat.

Answer 1

$\dfrac{^{n+k)}1}{\ \ \ n}-\dfrac{^{n)}1}{\ \ n+k} = \dfrac{\not{n}+k-\not{n}}{n(n+k)}=\dfrac{k}{n(n+k)}$