Question

Найти общее решение дифференциального уравнения первого порядка

Answer 1

$y\, (e^{x}+1)\, dy-e^{x}\, dx=0\, \Big |:(e^{x}+1)\ne 0\\\\\int y\, dy=\int \frac{e^{x}\, dx}{e^{x}+1}\\\\\int y\, dy=\int \frac{d(e^{x}+1)}{e^{x}+1}\\\\\frac{y^2}{2}=ln|e^{x}+1|+C\\\\y^2=2\, ln(e^{x}+1)+2C\\\\y=\pm \sqrt{2\, ln(e^{x}+1)+2C}\\\\ili\\\\\frac{y^2}{2}=ln(e^{x}+1)+lnC\\\\\frac{y^2}{2}=ln\frac{e^{x}+1}{C}\\\\y^2=2\, ln\frac{e^{x}+1}{C}\\\\y^2=ln\Big (\frac{e^{x}+1}{C} \Big )^2\\\\y=\pm \sqrt{ln\frac{(e^{x}+1)^2}{C^2}}$