ABSTRACT
If a quantity y depends on and varies with a quantity x then the rate of change of y with respect to x is dy dx https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429294402/968186b9-ffa4-4f2b-aa54-7fc58a604561/content/eq3251.tif"/> . Thus, for example, the rate of change of pressure p with height h is dp dh https://s3-euw1-ap-pe-df-pch-content-public-p.s3.eu-west-1.amazonaws.com/9780429294402/968186b9-ffa4-4f2b-aa54-7fc58a604561/content/eq3252.tif"/> .
