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Exemplo 1 de Precalculus, 1.1 Functions and Function Notation
Determining If Menu Price Lists Are Functions
Problema e solução em inglês, como no livro original.
The coffee shop menu, shown in Figure 2 consists of items and their prices.
- ⓐ Is price a function of the item?
- ⓑ Is the item a function of the price?
Figure
2
Resolva no papel primeiro. Depois abra a solução um passo de cada vez e pare assim que conseguir terminar sozinho.
Solução
- ⓐ Let’s begin by considering the input as the items on the menu. The output values are then the prices. See Figure 3.
Figure 3
Each item on the menu has only one price, so the price is a function of the item.
- ⓑ Two items on the menu have the same price. If we consider the prices to be the input values and the items to be the output, then the same input value could have more than one output associated with it. See Figure 4.
Figure 4
Therefore, the item is a not a function of price.
- ⓐ Let’s begin by considering the input as the items on the menu. The output values are then the prices. See Figure 3.
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