Problem 17

Question

Sketch the graph of the function. $$ f(t)=|t|-t $$

Step-by-Step Solution

Verified
Answer
The graph is a horizontal line at 0 for \( t \geq 0 \) and a line with slope -2 for \( t < 0 \).
1Step 1: Analyze the Function
The given function is \( f(t) = |t| - t \). The absolute value function \( |t| \) outputs \( t \) when \( t \geq 0 \) and \( -t \) when \( t < 0 \). Let's analyze these two cases separately.
2Step 2: Case Analysis for \( t \geq 0 \)
For \( t \geq 0 \), we have \( |t| = t \). Therefore, the function simplifies to: \[ f(t) = t - t = 0. \]So for any \( t \geq 0 \), the function value is 0.
3Step 3: Case Analysis for \( t < 0 \)
For \( t < 0 \), \( |t| = -t \). The function becomes: \[ f(t) = -t - t = -2t. \] This indicates a linear graph with a slope of -2 for \( t < 0 \).
4Step 4: Sketch the Graph
To sketch the graph, observe the results from the previous steps:- For \( t \geq 0 \), draw a horizontal line at \( y = 0 \).- For \( t < 0 \), draw a line with a slope of -2 starting from the origin, heading downward as it moves left.The graph will be a horizontal line for non-negative values and a straight line with slope -2 for negative values.

Key Concepts

Piecewise FunctionsAbsolute Value FunctionLinear Function
Piecewise Functions
Piecewise functions are fascinating and versatile because they allow a function to behave differently over different parts of its domain. In the given exercise, the function is defined separately for different intervals of the variable \( t \). Specifically, it separates behavior at \( t=0 \).

- When dealing with piecewise functions, it is crucial to evaluate the conditions or intervals over which different expressions apply. This graph of \( f(t) = |t| - t \) behaves differently for \( t \geq 0 \) and \( t < 0 \). - For \( t \geq 0 \), the value of \( f(t) \) is constant, resulting in a horizontal line part on the graph. - For \( t < 0 \), we see a linear expression, forming a downward sloping line due to the negative sign.

The essence of a piecewise function is its ability to seamlessly draw from different function types to fit a problem space. Understanding these can help you make sense of graphs that aren't straightforward and appreciate the diversity in mathematical modeling.
Absolute Value Function
The absolute value function \( |t| \) plays a central role in the problem, characterized by returning the non-negative magnitude of \( t \), regardless of its sign. This mathematical tool checks whether a number is positive or negative, and then either returns it as it is or as its positive counterpart respectively.

- For \( t \geq 0 \), \( |t| = t \), which means if \( t \) is positive or zero, the function remains unaffected. This simplification results in the output of our piecewise function as \( f(t) = 0 \).- On the contrary, when \( t < 0 \), \( |t| \) turns to \( -t \), effectively flipping the value of the input to positive. This leads the sub-function \( f(t) \) to turn into \( -2t \), a linear expression with a descending perspective.

Absolute value functions are essential in handling real number problems, especially where the direction or sign of a value doesn't alter the ongoing analysis but only its magnitude is necessary.
Linear Function
The linear function segment of our exercise emerges in the interval where \( t < 0 \). When simplified, the original function \( f(t) = -2t \) showcases the characteristics of a straight line.

- A key feature of linear functions like \( -2t \) is that they produce a constant rate of change or a slope. In this instance, the slope is \(-2\), indicating that for every unit decrease in \( t \) (to the left on the graph), the function \( f(t) \) decreases by 2 units.
- Linear functions are plotted as straight lines on a graph, distinguished usually by their slope and y-intercept. However, in this expression \(-2t\), the slope is emphasized over the intercept since it crosses the origin when \( t=0 \).

Understanding linear functions is crucial for graph interpretation and creation, as they form the basis for prediction and trend analysis models in both pure and applied mathematical areas.