Question Details

Which of the following functions describe the graph shown in the below figure?

Options

A

𝑦 = ||π‘₯| + 1| βˆ’ 2

B

𝑦 = ||π‘₯| βˆ’ 1| βˆ’ 1

C

𝑦 = ||π‘₯| + 1| βˆ’ 1

D

𝑦 = ||π‘₯ βˆ’ 1| βˆ’ 1|

Correct Answer :

𝑦 = ||π‘₯| βˆ’ 1| βˆ’ 1

Solution :

The correct answer is:
y=||x|-1|-1

By analyzing the provided graph, we can identify several key coordinates and features:
1. The local minimums (bottom peaks/cusps) are located at (-1,-1) and (1,-1).
2. The local maximum is at the origin (0,0).
3. The graph crosses the x-axis (x-intercepts) at (-2,0) and (2,0).
4. The graph passes through the points (-3,1) and (3,1).

We can verify the correct function by substituting these x-values:
β€’ For x=0:
y=||0|-1|-1=|0-1|-1=1-1=0
This correctly corresponds to the point (0,0).
β€’ For x=Β±1:
y=||Β±1|-1|-1=|1-1|-1=0-1=-1
This correctly corresponds to the vertices at (-1,-1) and (1,-1).
β€’ For x=Β±2:
y=||Β±2|-1|-1=|2-1|-1=1-1=0
This correctly corresponds to the x-intercepts at (-2,0) and (2,0).

Alternatively, we can understand the graph step-by-step through transformations:
1. Start with the parent absolute value function: y1=|x| (V-shape with vertex at (0,0)).
2. Shift down by 1 unit: y2=|x|-1 (vertex shifts to (0,-1)).
3. Reflect negative parts: Applying the outer absolute value y3=||x|-1| reflects the portion below the x-axis upwards. The vertex at (0,-1) reflects to (0,1), and new cusps are formed on the x-axis at (-1,0) and (1,0).
4. Final Shift down by 1 unit: Subtracting 1 to get y=||x|-1|-1 shifts the entire graph down. The peak at (0,1) shifts to (0,0) and the cusps shift down to (-1,-1) and (1,-1), perfectly matching the given graph.

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