transformation of function

Rearrangement of a mathematical formula or formulae to give a different subject. For example, in the formula A = bh, A is the subject of the formula. It can be rearranged as b = A ÷ h, where b is the subject, or as h = A ÷ b, where h is the subject.

The variable that becomes the subject of the formula should be written on its own on the left-hand side of the formula.

Use of inverses To transform a formula inverse functions can be used. Multiplication and division are inverses, as are addition and subtraction.

Flowcharts A flowchart is a good method that uses inverses to transform a formula. For example, to make r the subject of the formula D = 2r:

So r = D/2.

In a more complicated example, the formula used to convert temperatures from degrees Celsius to degrees Fahrenheit is

F = 9/5C + 32.

To make C the subject of the formula:

Therefore, C = 5(F − 32)/9.