Learning Resources
Using the Subsets to Define Domain and Range
Answers to pre-test |
| 1 (a) natural numbers |
| (b) positive real numbers |
| (c) integers |
| (d) rational numbers (non-negative) |
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2 (a) The temperature in the house is 20 °C or greater. If t represents temperature, t ³ 20 |
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(b) The temperature in the house is less than 20 °C. If t represents temperature, t < 20 |
| 3 (a) Non-negative rational numbers |
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(b) She will cut zero dresses if she doesn't work She will cut 7.5 dresses if she works the maximum 5 hr. The number of possible dresses falls between 0 and 7.5 Mathematically: 0 £ x £ 7.5, where x Î Q |
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(c) Her pay is 10 times the number of dresses cut
out. Mathematically: y = $10x and the inequality for this is 0 £ y £ 75, where y Î R |
| 4 (a) Smallest x-coordinate on both graphs is -1 |
| (b) Largest x-coordinate on both graphs is 2 |
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(c) For Graph 1, x can be any real number between -1 and 2 For Graph 2, x can only be an integer between -1 and 3. For example, there are no points with x-coordinates between -1 and 0. |
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(d) Graph 1 domain = {x | -1 £ x £
2, where x Î R} Graph 2 domain = {x | -1 £ x £ 2, where x Î I} |
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(e) For Graph 1, y can be any real number between -3 and 3 For Graph 2, y can only be an integer between -3 and 3 Graph 1 range = {y | -3 £ y £ 3, where y Î R} Graph 2 range = {y | -3 £ y £ 3, where y Î I} |