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Graph each case separately and then combine them. Begin by finding the boundary lines. Be careful about the domain of each case. When you test a point, choose the points from the corresponding domains.
We have been given an inequality.
g(x) >
|x+1| if x≤ -4
- |x| if - 4 < x < 2
|x-4| if x ≥ 2
We will first graph each case of the inequality separately. Then we will combine them on the same coordinate plane. Let's start with the first case. We will begin by determining it boundary line. To do that we replace the inequality symbol with the equals sign.
&Case I &&Boundary Line
& g(x) > |x+1| && g(x) = |x+1|
For the first case, the domain is the x-values less than or equal to -4, so the boundary line will be bound by x=-4 on the right. We will indicate its right endpoint with a closed point because the inequality that represents the restriction is non-strict.
Now we will test a point to decide which region we should shade. Let's test the point (-5,5)!
The point satisfied the inequality, so we will shade the region that contains point.
Applying the same steps, other cases can be graphed.
| Case | Boundary Line | Domain | Transformation of f(x)=|x| | Graph | Testing a Point | Inequality |
|---|---|---|---|---|---|---|
| g(x) > |x+1| | g(x) = |x+1| | x ≤ -4 | Translation 1 unit to the left | 5 ? > | -5+1| ⇓ 5> 4 | ||
| g(x) > - |x| | g(x) = - |x| | -4 < x < 2 | Reflection in the x-axis | 2 ? > -| 0| ⇓ 2> 0 | ||
| g(x) > |x-4| | g(x) = |x-4| | x ≥ 2 | Translation 4 units to the right | 4 ? > | 4-4| ⇓ 4> 0 |
Finally, we can combine the each case.