209. y= 3/√x³

$$y = \frac{3}{\sqrt{x^3}} = 3 x^{-\frac{3}{2}}$$ $$y' = 3 \cdot (-\frac{3}{2}) x^{-\frac{3}{2} - 1} = -\frac{9}{2} x^{-\frac{5}{2}} = -\frac{9}{2 \sqrt{x^5}}$$ Ответ: $$y' = -\frac{9}{2 \sqrt{x^5}}$$