Note 5 — Chapter XVIII · INTEGRATING AS THE REVERSE OF DIFFERENTIATING.
Reading edition
[You may ask, what has become of the little at the end? Well, remember that it was really part of the differential coefficient, and when changed over to the right-hand side, as in the , serves as a reminder that is the independent variable with respect to which the operation is to be effected; and, as the result of the product being totalled up, the power of has increased by one. You will soon become familiar with all this.]
[6] See p. 206 for integration between limits.