미분방정식 $\displaystyle \frac{dy} {dx} = \frac{1} {x \left (x^6 -1 \right)}$, $\displaystyle y \left (\frac{1} {\sqrt {2}} \right) =0$ 을 풀면?

• ①$\displaystyle x^6 = \frac{1} {2 \left (1+3e^ {6y} \right)}$
• ②$\displaystyle x^6 = \frac{1} {2 \left (1+3e^ {-6y} \right)}$
• ③$\displaystyle x^6 = \frac{1} {1+7e^ {6y}}$
• ④$\displaystyle x^6 = \frac{1} {1+7e^ {-6y}}$