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Упрости каждое выражение:
\(\dfrac{1}{(n+2)!}-\dfrac{1}{n+1}!+\dfrac{1}{n}!=\)
\(\dfrac{1-n(n+2)+(n+1)(n+2)}{(n+2)!}=\)
\(\dfrac{1-n-2+n^2+n+2n+2}{(n+2)!}=\dfrac{n^2+2n+1}{(n+2)!}=\dfrac{(n+1)^2}{(n+2)!}.\)
а) \(\dfrac{1}{n!}-\dfrac{1}{n+1}=\) [ ];
б) \(\dfrac{1}{(n+2)!}-\dfrac{1}{(n+1)!}=\) [ ];
в) \(\dfrac{1}{(n+1)!}+\dfrac{1}{(n-1)!}-\dfrac{1}{n!}=\) [ ].