dy/dx = sec(y/x) + y/x Let a = y/x then y = ax so, dy/dx = (x)da/dx + a
Substituting, we have
(x)da/dx + a = sec(a) + a or (x)da/dx = sec(a) then da/sec(a) = dx/x = cos(a) da
Integrating, we have sin(a) = ln(x) + constant or sin(a) = { ln(x) + ln(K) } = ln(Kx)
Therefore, a = sin-1(ln(Kx)) then y/x = sin-1(ln(Kx))
Finally, y = (x)sin-1(ln(Kx)) (K = constant)