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Tool to find the domain of definition of a function f(x): the set of values x which exists through f.

Answers to Questions

How to calculate the domain of definition of a function?

One has to observe values for which the function does not exists, there are generally 3 cases for real functions:

- division by 0 (denominator null), because 0 has no inverse

- negative square root (sqrt(x) is only defined for x ≥ 0)

- negative logarithm (log(x) is only defined for x > 0)

dCode has to calculate values with no inverse by f, and return the interval that corresponds to the domain of definition of f.

$$ f(x) = \sqrt{1-2x} \\ f(x) \text{ exists if } x <= 1/2 \\ D = ] -\infty ; 1/2 ] $$

What is an antecedent?

Consider a function y = f (x) then the number y is called the image of x, and x is called an antecedent of y with the function f in the definition domain D.

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