1. Graphing Quadratic Functions
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Make a table of values and connect the points with a parabola.
Graph:
Domain: { all real numbers }
Range: { y | y≥ 5 }
We want to graph the given quadratic function.
y=2x^2+4x+7
To do so, we will first make a table of values.
| x | 2x^2+4x+7 | y=2x^2+4x+7 |
|---|---|---|
| - 3 | 2( - 3)^2+4( - 3)+7 | 13 |
| - 2 | 2( - 2)^2+4( - 2)+7 | 7 |
| - 1 | 2( - 1)^2+4( - 1)+7 | 5 |
| 0 | 2( 0)^2+4( 0)+7 | 7 |
| 1 | 2( 1)^2+4( 1)+7 | 13 |
Now, let's plot the obtained points and connect them with a parabola.
We can see above that the x-variable can take any value. Conversely, the y-variable only takes values greater than or equal to 5. Using this information, we can write the domain and range of the function. Domain:& { all real numbers } Range:& { y | y≥ 5 }