\[f(x) = e^{\frac{x}{3}};\]
\[1)\ f^{'}(x) = \frac{1}{3} \bullet e^{\frac{x}{3}};\]
\[f^{'}\left( x_{0} \right) = \frac{1}{3}e^{\frac{x_{0}}{3}};\]
\[f\left( x_{0} \right) = e^{\frac{x_{0}}{3}};\]
\[y = e^{\frac{x_{0}}{3}} + \frac{1}{3}e^{\frac{x_{0}}{3}}\left( x - x_{0} \right)\text{.\ }\]
\[2)\ Проходит\ через\ начало:\]
\[0 = e^{\frac{x_{0}}{3}} + \frac{1}{3}e^{\frac{x_{0}}{3}}\left( 0 - x_{0} \right)\]
\[3e^{\frac{x_{0}}{3}} - e^{\frac{x_{0}}{3}} \bullet x_{0} = 0\]
\[3 - x_{0} = 0\]
\[x_{0} = 3;\]
\[f\left( x_{0} \right) = e^{\frac{3}{3}} = e;\]
\[Ответ:\ \ (3;\ e).\]