แก้โจทย์ V=1/3pia^2h.quada=6.quadh=1

$$V = \frac { 1 } { 3 } \pi a ^ { 2 } h . \quad a = 6 . \quad h = 1$$

หาค่า a (complex solution)

$$\left\{\begin{matrix}a=-\left(\pi h\right)^{-\frac{1}{2}}\sqrt{3V}\text{; }a=\left(\pi h\right)^{-\frac{1}{2}}\sqrt{3V}\text{, }&h\neq 0\\a\in \mathrm{C}\text{, }&V=0\text{ and }h=0\end{matrix}\right.$$

หาค่า V

$$V=\frac{\pi ha^{2}}{3}$$

หาค่า a

$$\left\{\begin{matrix}a=\sqrt{\frac{3V}{\pi h}}\text{; }a=-\sqrt{\frac{3V}{\pi h}}\text{, }&\left(V\geq 0\text{ and }h>0\right)\text{ or }\left(V\leq 0\text{ and }h<0\right)\\a\in \mathrm{R}\text{, }&V=0\text{ and }h=0\end{matrix}\right.$$