\[\boxed{\mathbf{983}\mathbf{.}}\]
\[1)\ F(x) = \frac{x^{6}}{6}\text{\ \ }и\ \ f(x) = x^{5};\]
\[F^{'}(x) = \frac{1}{6} \bullet \left( x^{6} \right)^{'} = \frac{1}{6} \bullet 6x^{5} =\]
\[= x^{5} = f(x).\]
\[2)\ F(x) = \frac{x^{5}}{5} + 1\ \ и\ \ f(x) = x^{4};\]
\[F^{'}(x) = \frac{1}{5} \bullet \left( x^{5} \right)^{'} + (1)^{'} =\]
\[= \frac{1}{5} \bullet 5x^{4} + 0 = x^{4} = f(x).\]