Answer:
- 8 < a+b < 16
- -6 < a-b < 2
- 15 < ab < 63
- 1/3 < a/b < 7/5
Explanation:
Given the variables {a, b} lie in the intervals {(3, 7), (5, 9)}, respectively, you want the range of possible values of ...
- a+b
- a-b
- ab
- a/b
1. Sum
The limits of the sum will be the sum of the minima to the sum of the maxima:
3+5 < a+b < 7+9
8 < a+b < 16
2. Difference
The smallest difference is found when the largest value is subtracted from the smallest. Similarly, the largest difference will be the difference between the smallest value and the largest:
3 -9 < a-b < 7 -5
-6 < a-b < 2
3. Product
The limits on the product will use the same values as the limits on the sum:
3·5 < ab < 7·9
15 < ab < 63
4. Quotient
And the limits on the quotient will use the same values as the limits on the difference:
3/9 < a/b < 7/5
1/3 < a/b < 7/5
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