As a preservatives, Glacial Acetic Acid can be used in a wide variety of industries including: food production, beverage, pharmaceutical, agriculture/animal feed, and various other industries.
The difference quotient is a measure of the average rate of change of the function over an interval (in this case, an interval of length h). The limit of the difference quotient (i.e., the derivative) is thus the instantaneous rate of change.
When you first heard the term 'difference quotient', you may have drawn a blank. After all, it involves so many elements, like functions, and secants, and graphs, and even worse, a crazy formula that brings it all together.