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If π is a function from the set π to the set π, what do we call π?
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Remember, a function is a special type of relation or mapping that maps elements from one set onto exactly one element in the second set.
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In this case, our function π maps elements from the set π to the set π.
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If we say that lowercase π₯ is some element of set π and lowercase π¦ is some element in set π, then we can represent this by saying π¦ is equal to π of π₯; π¦ is some function of π₯.
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And when we think about functions, there are two special words we use to describe the relevant sets.
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The elements in set π , which weβve defined to be lowercase π₯, are all possible inputs to the function.
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And the elements in set π, which weβve defined to be lowercase π¦, are all possible outputs.
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And when we think about the set of possible inputs of a function, weβre thinking about the domain of the function, whilst when we think about the set of possible outputs, weβre thinking about its range.
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The question asks us here βwhat do we call π?β
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Since π is the set of possible inputs for our function π, then π is the domain of the function.