The general solution of the differential equation $x \cos \frac{y}{x}(y d x+x d y)=y \sin \frac{y}{x}(x d y-y d x)$ is
- A
$\log (x y)=\log \cos \frac{x}{y}+C$
- B
$\cos \left(\frac{y}{x}\right)=\frac{C}{x y}$
- C
$\log (x y)=\log \sec \frac{x}{y}+C$
- D
$x+y+C=0$
✓ Correct answer: B
Want the full step-by-step reasoning?