Question

Find the integral of (y2 -1) dx-2dy = 0

Answer 1

$(y^2-1)dx=2dy,$

$\frac 12 x=\frac 12\ln\frac{1-y}{1+y}+\frac 12 \ln c,$

$y=\frac{1-e^{2c+x}}{1+e^{2c+x}}.$