At vero eos et accusamus et iusto odio dignissimos ducimus qui blanditiis praesentium voluptatum deleniti atque corrupti quos dolores et quas molestias excepturi sint occaecati cupiditate non provident, similique sunt in culpa qui officia deserunt mollitia animi, id est laborum et dolorum fuga.
Et harum quidem rerum facilis est et expedita distinctio. Nam libero tempore, cum soluta nobis est eligendi optio cumque nihil impedit quo minus id quod maxime placeat facere possimus, omnis voluptas assumenda est, omnis dolor repellendus.
Itaque earum rerum hic tenetur a sapiente delectus, ut aut reiciendis voluptatibus maiores alias consequatur aut perferendis doloribus asperiores repellat.
the d tells you what variable you are taking the integral with respect to, eg dx means the integral with respect to x, dy means integral with respect to y, when you are doing calculus with only one variable this may not mean much, however once you get into multi variable calculus and differential equations you will need to know what variable you are integrating and which you are treating like constants that just hang on for the ride
Thank you so much!
not a problem, its much like when you have d/dx for a derivative with respect to x, you will see the same thing happens with partial derivatives where you need to know which variable to differentiate, to denote a partial they simply used a squrly looking d and put it over the variable you are differentiating with respect to