I'm stuck with two problems that are aimed at introducing shortly the method of variation of parameters in order to solve a differential equation. The problems are:
$x\cdot y(x)'+y(x)=x^2;\ y(1)=1$
and
$u'(t)+\frac{u}{1+t}=exp(2t);\ u(0)=4.$
I have tried to understand the method, but I have not arrived anywhere yet. Can someone please help me get started?
-Marie :)