Exact differential equations. Test to tel if its exact not valid, am I doing something wrong? I got this differential equation:
$$(y^{3} + \cos t)'y = 2 + y \sin t,\text{ where }y(0) = -1$$
Tried to check for $dM/dY = dH/dY$ but I cant seem to get them alike. So what would the next step be to solve this problem?

A related problem. Here is how to start. Write the ode as
$$ (y^3 + \cos t)\frac{dy}{dx} = 2 + y \sin t   \implies (y^3 + \cos t){dy} - (2 + y \sin t)dx=0 .$$
Now, you should be able to proceed.
