ABSTRACT
At the end of this chapter, you should be able to:
• define ‘subject of the formula’ • transpose equations whose terms are connected by plus and/or minus signs • transpose equations that involve fractions • transpose equations that contain a root or power • transpose equations in which the subject appears in more than one term
In the formula I = V R
, I is called the subject of the formula. Similarly, in the formula y = mx + c, y is the subject of the formula. When a symbol other than the subject is required to be the subject, the formula needs to be rearranged to make a new subject. This rearranging process is called transposing the formula or transposition. For example, in the above formulae,
if I = V R
then V = IR
and if y = mx + c then x = y − c m
How did we arrive at these transpositions? This is the purpose of this chapter – to show how to transpose formulae. A great many equations occur in engineering and it is essential that we can transpose them when needed.
