Hi

i have a few question i am having trouble solving:

Could someone tell me where my mistakes are.

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

$\displaystyle \frac{dy}{dx}+y=xy^3$

$\displaystyle \frac{dy}{dx}-y^{-2}=\frac{-1}{x}$

$\displaystyle I=e^{-x}$

$\displaystyle e^{-x}(\frac{dy}{dx}-y^2)=\frac{e^{-x}}{x}$

$\displaystyle e^{-x}y=\frac{e^{-x}}{x}$

what should i do next if this is correct.

2) $\displaystyle xcosy\frac{dy}{dx}-siny=0$

someone tell me how to start this?

i tried to integrate from this:

$\displaystyle \frac{dy}{dx} -tany = \frac{1}{x}$

but this didn't work.

P.S