Click in the blank spaces in Table 1 below to reveal the values from the ordered pairs in section 2. The ordered pairs in section 1 of this lesson can also be represented in a table. In a table, like the one below, the domain is usually listed in the left column and the range is listed in the right column. You can also refer to the domain as the input values, x, and the range as the output values, y, in a relation or function.
Click in the blank spaces in Table 1 below to reveal the values from the ordered pairs in section 2.
Since a table is just another representation of the ordered pairs, the domain and range are the same.
D: {90, 180, 270, 360}
R: {3.8, 8.0, 12.5, 17.4}
Let’s look at another problem.
The domain of the function f(x) = √4x + 1 is 1 over 4
-
1
4
, 0, 2, 6, and 12. What is the range of the function? Before you answer, copy the table below onto a sheet of paper. Fill in the missing values. Click on the empty spaces to check your answers.
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R = {0, 1, 3, 7}
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When you evaluate each x-value in the function, the result is the output value. These output values are the range.
Domain and range help connect between the independent and dependent variables of a function. They can also help you make reasonable conclusions about what values are acceptable in each domain and range set.
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Replacing x is -2 will result in a negative number under the square root. Since you cannot take the square root of a negative number and get a real number, -2 could never be in the domain.
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Since evaluating the expression with any number less than 1 over 4 - 1 4 would result in a negative number under the square root, you can conclude that any number less than 0 would not be in the range.
Number of sides of a regular polygon |
Sum of the degress of the interior angles |
3 |
180 |
4 |
360 |
5 |
540 |
6 |
720 |
7 |
900 |
8 |
1080 |
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The domain is the set of values in the left column.
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D: {3, 4, 5, 6, 7, 8}
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The range is the set of values in the right column.
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R: {180, 360, 540, 720, 900, 1080}
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In this instance, the independent variable is the number of sides of a regular polygon. Think about the number of sides it takes to make a polygon.
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The dependent variable represents the sum of the degrees of a regular polygon. Think about what values would not be a reasonable sum.