\[\boxed{\mathbf{783}\mathbf{.}}\]
\[s(t) = t^{2} + 2\]
\[Мгоновенная\ скорость:\]
\[\mathrm{\Delta}s = \frac{f(t + h) - f(t)}{h} =\]
\[= \frac{(t + h)^{2} + 2 - t^{2} - 2}{h} =\]
\[= \frac{t^{2} + 2th + h^{2} - t^{2}}{h} =\]
\[= \frac{2th + h^{2}}{h} = 2t + h\]
\[v = \lim_{h \rightarrow 0}(2t + h) = 2t + 0 = 2t.\]
\[1)\ t = 5:\]
\[v(5) = 2 \bullet 5 = 10.\]
\[2)\ t = 10:\]
\[v(10) = 2 \bullet 10 = 20.\]