Math Problem Statement

Represent \( f(t) \) using a combination of Heaviside step functions and find its Laplace transform \( F(s) = \mathcal{L}\{f(t)\} \).

Solution

Let's address each part of the problem systematically.

Part (a): Representing f(t)f(t) using Heaviside Step Functions

The function f(t)f(t) is given by: f(t)=2t2h(t2)h(t4)+4h(t4)h(t9)f(t) = 2t - 2 \, h(t - 2) - h(t - 4) + 4 \, h(t - 4) - h(t - 9) where h(tc)h(t - c) represents the Heaviside step function hc(t)h_c(t), which is 0 when t<ct < c and 1 when tct \geq c.

The function f(t)f(t) appears to change its form at specific points t=2t = 2, t=4t = 4, and t=9t = 9. We interpret each term in f(t)f(t) based on these changes:

  1. For t<2t < 2: The Heaviside functions are all 0, so f(t)=2tf(t) = 2t.
  2. For 2t<42 \leq t < 4: The term h(t2)h(t - 2) is active, modifying f(t)f(t) to 2t22t - 2.
  3. For 4t<94 \leq t < 9: Both h(t2)h(t - 2) and h(t4)h(t - 4) are active, making f(t)=2t21+4=2t+1f(t) = 2t - 2 - 1 + 4 = 2t + 1.
  4. For t9t \geq 9: All terms are active, resulting in f(t)=2t+11=2tf(t) = 2t + 1 - 1 = 2t.

Part (b): Finding the Laplace Transform F(s)=L{f(t)}F(s) = \mathcal{L}\{f(t)\}

To find the Laplace transform of f(t)f(t), we calculate the Laplace transform of each segment, taking into account the Heaviside functions.

Let me know if you would like detailed steps for computing the Laplace transforms for each segment of f(t)f(t), or if you have any specific questions about the setup.


Here are some related questions to expand on this topic:

  1. How do Heaviside functions help in defining piecewise functions?
  2. What is the general form of the Laplace transform for a shifted Heaviside function?
  3. How do Laplace transforms simplify solving differential equations?
  4. What are the applications of Heaviside functions in engineering and physics?
  5. How would the Laplace transform change if f(t)f(t) had an exponential decay factor?

Tip: When dealing with piecewise functions, breaking down the function using Heaviside functions can greatly simplify Laplace transform calculations.

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Math Problem Analysis

Mathematical Concepts

Laplace Transform
Heaviside Step Functions
Piecewise Functions

Formulas

Laplace Transform formula for \( f(t) \): \( F(s) = \mathcal{L}\{f(t)\} \)
Heaviside Step Function \( h(t - c) \), which is 0 when \( t < c \) and 1 when \( t \geq c \)

Theorems

Laplace Transform of Shifted Heaviside Functions

Suitable Grade Level

Undergraduate - Engineering or Advanced Calculus