(a) Find Wronskian $W(y_1,y_2)(x)$ of a fundamental set of solutions $y_1(x) , y_2(x)$ for ODE
\begin{equation*}
\bigl(x\sin(x)+\cos(x)\bigr)y''-x\cos(x)y'+\cos(x)y=0
\end{equation*}
(b) Check that $y_1(x)=x$ is a solution and find another linearly independent solution.
(c) Write the general solution, and find solution such that ${y(0)=1, y'(0)=1}$.