Given the equation:
$$x y{\left(x \right)} \frac{d}{d x} y{\left(x \right)} - y^{2}{\left(x \right)} - y{\left(x \right)} \frac{d}{d x} y{\left(x \right)} + 1 = 0$$
This differential equation has the form:
f1(x)*g1(y)*y' = f2(x)*g2(y),
where
$$\operatorname{f_{1}}{\left(x \right)} = 1$$
$$\operatorname{g_{1}}{\left(y \right)} = 1$$
$$\operatorname{f_{2}}{\left(x \right)} = - \frac{1}{x - 1}$$
$$\operatorname{g_{2}}{\left(y \right)} = - \frac{y^{2}{\left(x \right)} - 1}{y{\left(x \right)}}$$
We give the equation to the form:
g1(y)/g2(y)*y'= f2(x)/f1(x).
Divide both parts of the equation by g2(y)
$$- \frac{y^{2}{\left(x \right)} - 1}{y{\left(x \right)}}$$
we get
$$- \frac{y{\left(x \right)} \frac{d}{d x} y{\left(x \right)}}{y^{2}{\left(x \right)} - 1} = - \frac{1}{x - 1}$$
We separated the variables x and y.
Now, multiply the both equation sides by dx,
then the equation will be the
$$- \frac{dx y{\left(x \right)} \frac{d}{d x} y{\left(x \right)}}{y^{2}{\left(x \right)} - 1} = - \frac{dx}{x - 1}$$
or
$$- \frac{dy y{\left(x \right)}}{y^{2}{\left(x \right)} - 1} = - \frac{dx}{x - 1}$$
Take the integrals from the both equation sides:
- the integral of the left side by y,
- the integral of the right side by x.
$$\int \left(- \frac{y}{y^{2} - 1}\right)\, dy = \int \left(- \frac{1}{x - 1}\right)\, dx$$
Detailed solution of the integral with yDetailed solution of the integral with xTake this integrals
$$- \frac{\log{\left(y^{2} - 1 \right)}}{2} = Const - \log{\left(x - 1 \right)}$$
Detailed solution of the equationWe get the simple equation with the unknown variable y.
(Const - it is a constant)
Solution is:
$$\operatorname{y_{1}} = y{\left(x \right)} = - \sqrt{C_{1} x^{2} - 2 C_{1} x + C_{1} + 1}$$
$$\operatorname{y_{2}} = y{\left(x \right)} = \sqrt{C_{1} x^{2} - 2 C_{1} x + C_{1} + 1}$$