Approaches of Utility - Cardinal Utility
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A simple example of two cardinal utility functions of y=2x+3
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Cardinal utility
In economics, a cardinal utility function or scale is a utility index that preserves preference orderings uniquely up to positive affine transformations. Two utility indices are related by an affine transformation if for every value 
of one index u, occurring at quantity 
of the goods bundle being evaluated, the corresponding value 
of the other index v satisfies a relationship of the form
of one index u, occurring at quantity of the goods bundle being evaluated, the corresponding value of the other index v satisfies a relationship of the form
,
for fixed constants a and b. Thus the utility functions themselves are related by
The two indices differ only with respect to scale and origin.[1]
The idea of Cardinal utility is considered outdated except for specific contexts such as decision making under risk, utilitarian welfare evaluations, and discounted utilities for intertemporal evaluationswhere it is still applied. Elsewhere, such as in general consumer theory, ordinal utility is preferred.
A simple example of two cardinal utility functions of y=2x+3
