Which one of the given figures P, Q, R and S represents the graph of the following function? $f(x) = | |x + 2| - |x - 1| |$
The correct answer is
P
To solve this problem, we need to understand the behavior of the function \(f(x) = ||x + 2| - |x - 1||\) and match it with one of the given graphs. Let's analyze the function step by step:
Step 1: Break Down the Absolute Value Expressions
The function involves absolute values, which means it will have different expressions based on the sign of the expressions inside the absolute values.
Consider the critical points where the expressions inside the absolute values change sign: \(x = -2\) and \(x = 1\).
Step 2: Evaluate the Function in Different Intervals
\(x \leq -2\): Both \(x + 2\) and \(x - 1\) are negative.
The function simplifies to: \(f(x) = |-(x + 2) - (-(x - 1))| = |-x - 2 + x - 1| = |(-3)| = 3\).
\(-2 \lt x \leq 1\): \(x + 2\) is positive, \(x - 1\) is negative.
The function simplifies to: \(f(x) = |(x + 2) - (-(x - 1))| = |x + 2 + x - 1| = |2x + 1|\).
\(x \gt 1\): Both \(x + 2\) and \(x - 1\) are positive.
The function simplifies to: \(f(x) = |(x + 2) - (x - 1)| = |x + 2 - x + 1| = |3| = 3\).
Step 3: Sketch the Graph
In the intervals \(x \leq -2\) and \(x \gt 1\), the function is constant with a value of 3.
In the interval \(-2 \lt x \leq 1\), the function is a linear function \(|2x + 1|\), which forms a 'V' shape at \(x = -\frac{1}{2}\).
Conclusion
Based on the analysis above, graph "P" displays constant values of 3 for \(x \leq -2\) and \(x \gt 1\), and a 'V' shape between \(x = -2\) and \(x = 1\).
Thus, the correct graph that represents the function is graph "P".
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Important Questions from Absolute Value Function
Which one of the following plots represents $f(x) = -\frac{|x|}{x}$, where x is a non-zero real number? Note: The figures shown are representative.