\[1)\ y = x^{2} - 2x,\ \ \ x_{0} = 3:\]
\[y(3) = 9 - 6 = 3;\]
\[y^{'}(x) = 2x - 2;\]
\[y^{'}(3) = 6 - 2 = 4;\]
\[y = 3 + 4(x - 3) = 4x - 9.\]
\[Ответ:\ \ y = 4x - 9.\]
\[2)\ y = x^{3} + 3x,\ \ \ x_{0} = 3:\]
\[y(3) = 27 + 9 = 36;\]
\[y^{'}(x) = 3x^{2} + 3;\]
\[y^{'}(3) = 27 + 3 = 30;\]
\[y = 36 + 30(x - 3) = 30x - 54.\]
\[Ответ:\ \ y = 30x - 54.\]
\[3)\ y = \sin x,\ \ \ x_{0} = \frac{\pi}{6}:\]
\[y\left( \frac{\pi}{6} \right) = \sin\frac{\pi}{6} = \frac{1}{2};\]
\[y^{'}(x) = \cos x;\]
\[y^{'}\left( \frac{\pi}{6} \right) = \cos\frac{\pi}{6} = \frac{\sqrt{3}}{2};\]
\[y = \frac{1}{2} + \frac{\sqrt{3}}{2}\left( x - \frac{\pi}{6} \right) =\]
\[= \frac{\sqrt{3}}{2}x + \frac{1}{2} - \frac{\pi\sqrt{3}}{12}.\]
\[Ответ:\ \ y = \frac{\sqrt{3}}{2}x + \frac{1}{2} - \frac{\pi\sqrt{3}}{12}.\]
\[4)\ y = \cos x,\ \ \ x_{0} = \frac{\pi}{3}:\]
\[y\left( \frac{\pi}{3} \right) = \cos\frac{\pi}{3} = \frac{1}{2};\]
\[y^{'}(x) = - \sin x;\]
\[y^{'}\left( \frac{\pi}{3} \right) = - \cos\frac{\pi}{3} = - \frac{\sqrt{3}}{2};\]
\[y = \frac{1}{2} - \frac{\sqrt{3}}{2}\left( x - \frac{\pi}{3} \right) =\]
\[= - \frac{\sqrt{3}}{2}x + \frac{1}{2} + \frac{\pi\sqrt{3}}{6}.\]
\[Ответ:\ \ y = - \frac{\sqrt{3}}{2}x + \frac{1}{2} + \frac{\pi\sqrt{3}}{6}.\]