V = IR, I = V/R, and R = V/I is not a set of three equations: it is a set of three representations of one equation. An equation is a relationship between variables. All three elements of the set represent the same relationship between variables. Each element is a different representation of the same relationship.
Daniel Crowe
Loudoun County Public Schools
Academy of Science
dan.crowe@lcps.org
Ken Caviness 06/29/13 8:30 AM >>>
In University Physics, I tell the class about my surprise when I picked up a ham radio test review book and found a lengthy explanation to help learn "the three equations" of Ohm's Law. They showed a circle, bisected horizontally, with the lower half bisected again, vertically. The letters V, I and R were placed in the three areas created, V on top, I R below. Then they said to cover up with your thumb whatever you were trying to solve for. Covering up the V left I R side-by-side (multiplied), covering up the I left V over R, etc.
Cute, but my point (and yours) is that there is absolutely no need to learn 3 equations in any case.