Question

Find the general solution of (x+3)y’=2y

Answer 1

Answer:

$y=C(x+3)^2$

Step-by-step explanation:

We are given:

$\displaystyle (x+3)y^\prime=2y$

Separation of Variables:

$\displaystyle \frac{1}{y}\frac{dy}{dx}=\frac{2}{x+3}$

So:

$\displaystyle \frac{dy}{y}=\frac{2}{x+3} \, dx$

Integrate:

$\displaystyle \int\frac{dy}{y}=\int\frac{2}{x+3}\, dx$

Integrate:

$\displaystyle \ln|y|=2\ln|x+3|+C$

Raise both sides to e:

$|y|=e^{2\ln|x+3|+C}$

Simplify:

$|y|=(e^{\ln|x+3|})^2\cdot e^C$

So:

$|y|=C|x+3|^2$

Simplify:

$y=\pm C(x+3)^2=C(x+3)^2$