$(x-1)y''-xy'+y=0$
$y_1(x)=e^x$ is a solution of this differential equation, but how can I find a second linearly independent solution?
Here is what I've done so far..
$y_2(x)=ue^x$
$y_2'=u'e^x+ue^x$
$y_2''=u''e^x+u'e^x+u'e^x+ue^x$
Substituting back into the ODE, I get
$(x-1)(u''e^x+u'e^x+u'e^x+ue^x)-x(u'e^x+ue^x)+ue^x=0$
If I simplify this, I get
$x(u''+u'+2u)-u''-2u'=0$ ... Do you get the same?
Now what do I do, if this is correct?
$$ (x-1)(u''e^x+u'e^x+u'e^x+ue^x)-x(u'e^x+ue^x)+ue^x \\ = x(u''e^x+u'e^x) - (u''e^x+2u'e^x) + xu'e^x + xue^x- x(u'e^x+ue^x) - ue^x+ ue^x \\ = x(u''e^x+u'e^x) - (u''e^x+2u'e^x) $$
So solve
$$ (x-1)u'' + (x-2)u' = 0 $$
i.e. solve
$$ (x-1)w' + (x-2)w = 0 $$
for $w$, then $u$ is an antiderivative of $w$ and $y_2 = ue^x$.