Rule 3: Product Rule

Product Rule

Recipe: $fg\prime +gf\prime$

Note : This recipe can be reversed because the terms are being added, 3+5 is the same as 5+3. So, your teacher might use this recipe in a reversed order, $gf\prime +fg\prime$. The recipes are still equal to each other. I recommend you choose one version of the recipe, and stick with it.