goals

If $$\cos\ y=x \cos(a+y)$$ then prove that:

$$\dfrac{dy}{dx}=\dfrac{\cos^{2}(a+y)}{\sin a}$$

$$\dfrac{dy}{dx}=\dfrac{\cos^{2}(a+y)}{\sin a}$$

The solution of $$ydx-xdy+\log {x}dx=0$$ is

The solution of $$ydx-xdy+\log {x}dx=0$$ is

The solution of $$ydx-xdy+\log {x}dx=0$$ is

The solution of $$ydx-xdy+\log {x}dx=0$$ is