question_answer 1)

If y = 3 cos (log x) + 4 sin (log x), show that x2y2 + xy1 + y = 0.  

Answer:

y = 3 cos (log x) + 4 sin (log x)                            Diff. agsin w.r.t. x.          X y2 + y1× 1 = ? 3 cos (log x)           = ?y           hence the result.