\[\boxed{\mathbf{987}\mathbf{.}}\]
\[1)\ F(x) = 3e^{\frac{x}{3}}\text{\ \ }и\ \ f(x) = e^{\frac{x}{3}};\]
\[F^{'}(x) = 3 \bullet \left( e^{\frac{x}{3}} \right)^{'} = 3 \bullet \frac{1}{3} \bullet e^{\frac{x}{3}} =\]
\[= e^{\frac{x}{3}} = f(x).\]
\[2)\ F(x) = \sin{2x}\ и\ \ \]
\[f(x) = 2\cos{2x};\]
\[F^{'}(x) = \left( \sin{2x} \right)^{'} = 2\cos{2x} =\]
\[= f(x).\]