1. **Stating the problem:** Solve the differential equation $$2(y')^2 = (y-1)y''$$ where $y' = \frac{dy}{dx}$ and $y'' = \frac{d^2y}{dx^2}$.
2. **Rewrite the equation:** Let $p = y'$, so $y'' = \frac{dp}{dx} = \frac{dp}{dy} \cdot \frac{dy}{dx} = p \frac{dp}{dy}$. Substitute into the equation:
$$2p^2 = (y-1) p \frac{dp}{dy}$$
3. **Simplify:** Divide both sides by $p$ (assuming $p \neq 0$):
$$2p = (y-1) \frac{dp}{dy}$$
4. **Separate variables:**
$$\frac{dp}{dy} = \frac{2p}{y-1}$$
Rewrite as
$$\frac{1}{p} dp = \frac{2}{y-1} dy$$
5. **Integrate both sides:**
$$\int \frac{1}{p} dp = \int \frac{2}{y-1} dy$$
This gives
$$\ln|p| = 2 \ln|y-1| + C$$
6. **Exponentiate:**
$$|p| = e^C |y-1|^2$$
Let $A = e^C > 0$, so
$$p = y' = A (y-1)^2$$
7. **Separate variables again:**
$$\frac{dy}{dx} = A (y-1)^2$$
Rewrite as
$$\frac{dy}{(y-1)^2} = A dx$$
8. **Integrate:**
$$\int (y-1)^{-2} dy = \int A dx$$
The integral on the left is
$$\int (y-1)^{-2} dy = - (y-1)^{-1} + C_1$$
So
$$- \frac{1}{y-1} = A x + C_2$$
9. **Solve for $y$:**
$$\frac{1}{y-1} = - A x - C_2$$
Let $B = -C_2$, then
$$\frac{1}{y-1} = - A x + B$$
Invert both sides:
$$y - 1 = \frac{1}{- A x + B}$$
10. **Final solution:**
$$\boxed{y = 1 + \frac{1}{B - A x}}$$
where $A$ and $B$ are arbitrary constants determined by initial conditions.
Differential Equation A4Ec96
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