Math Problem Statement

Solve the following Laplace transforms: 1. L{t^3e^{-7t}} 2. L{te^{10t}} 3. L{sin(5t)e^{-7t}} 4. L{e^{-4t} sin(2t)} 5. L{t(e^t + e^{2t})^2} 6. L{(1 - e^t + 2e^{-3t}) cos(6t)}

Solution

The image contains a list of Laplace transform problems labeled "Selesai transformasi Laplace berikut ini", which means "Solve the following Laplace transforms" in Indonesian. The problems are as follows:

  1. L{t3e7t}\mathcal{L} \{ t^3 e^{-7t} \}
  2. L{te10t}\mathcal{L} \{ t e^{10t} \}
  3. L{sin(5t)e7t}\mathcal{L} \{ \sin(5t) e^{-7t} \}
  4. L{e4tsin(2t)}\mathcal{L} \{ e^{-4t} \sin(2t) \}
  5. L{t(et+e2t)2}\mathcal{L} \left\{ t \left(e^t + e^{2t}\right)^2 \right\}
  6. L{(1et+2e3t)cos(6t)}\mathcal{L} \left\{ \left(1 - e^t + 2 e^{-3t}\right) \cos(6t) \right\}

I'll solve each of these transforms one by one.


  1. Problem: L{t3e7t}\mathcal{L} \{ t^3 e^{-7t} \}

    The Laplace transform of tneatt^n e^{-at} is: L{tneat}=n!(s+a)n+1\mathcal{L} \{ t^n e^{-at} \} = \frac{n!}{(s + a)^{n+1}} For t3e7tt^3 e^{-7t}: L{t3e7t}=3!(s+7)4=6(s+7)4\mathcal{L} \{ t^3 e^{-7t} \} = \frac{3!}{(s + 7)^4} = \frac{6}{(s + 7)^4}

  2. Problem: L{te10t}\mathcal{L} \{ t e^{10t} \}

    Using the general formula L{tneat}=n!(sa)n+1\mathcal{L} \{ t^n e^{at} \} = \frac{n!}{(s - a)^{n+1}} for teatt e^{at}: L{te10t}=1!(s10)2=1(s10)2\mathcal{L} \{ t e^{10t} \} = \frac{1!}{(s - 10)^2} = \frac{1}{(s - 10)^2}

  3. Problem: L{sin(5t)e7t}\mathcal{L} \{ \sin(5t) e^{-7t} \}

    The Laplace transform of sin(kt)eat\sin(kt) e^{-at} is: L{sin(kt)eat}=k(s+a)2+k2\mathcal{L} \{ \sin(kt) e^{-at} \} = \frac{k}{(s + a)^2 + k^2} For sin(5t)e7t\sin(5t) e^{-7t}: L{sin(5t)e7t}=5(s+7)2+25\mathcal{L} \{ \sin(5t) e^{-7t} \} = \frac{5}{(s + 7)^2 + 25} Simplifying the denominator: 5(s+7)2+25\frac{5}{(s + 7)^2 + 25}

  4. Problem: L{e4tsin(2t)}\mathcal{L} \{ e^{-4t} \sin(2t) \}

    Again, using the same formula for sin(kt)eat\sin(kt) e^{-at}: L{e4tsin(2t)}=2(s+4)2+4\mathcal{L} \{ e^{-4t} \sin(2t) \} = \frac{2}{(s + 4)^2 + 4} Simplifying: 2(s+4)2+4\frac{2}{(s + 4)^2 + 4}

  5. Problem: L{t(et+e2t)2}\mathcal{L} \left\{ t \left(e^t + e^{2t}\right)^2 \right\}

    First, expand (et+e2t)2\left(e^t + e^{2t}\right)^2: (et+e2t)2=e2t+2e3t+e4t\left(e^t + e^{2t}\right)^2 = e^{2t} + 2e^{3t} + e^{4t} Now, find the Laplace transform of t(e2t+2e3t+e4t)t \left( e^{2t} + 2e^{3t} + e^{4t} \right): L{te2t}=1(s2)2,L{te3t}=1(s3)2,L{te4t}=1(s4)2\mathcal{L} \left\{ t e^{2t} \right\} = \frac{1}{(s - 2)^2}, \quad \mathcal{L} \left\{ t e^{3t} \right\} = \frac{1}{(s - 3)^2}, \quad \mathcal{L} \left\{ t e^{4t} \right\} = \frac{1}{(s - 4)^2} So: L{t(et+e2t)2}=1(s2)2+21(s3)2+1(s4)2\mathcal{L} \left\{ t \left(e^t + e^{2t}\right)^2 \right\} = \frac{1}{(s - 2)^2} + 2 \frac{1}{(s - 3)^2} + \frac{1}{(s - 4)^2}

  6. Problem: L{(1et+2e3t)cos(6t)}\mathcal{L} \left\{ \left(1 - e^t + 2 e^{-3t}\right) \cos(6t) \right\}

    Break it into three parts: L{cos(6t)},L{etcos(6t)},L{e3tcos(6t)}\mathcal{L} \{ \cos(6t) \}, \quad \mathcal{L} \{ e^t \cos(6t) \}, \quad \mathcal{L} \{ e^{-3t} \cos(6t) \} Using the Laplace transform of cos(kt)eat\cos(kt) e^{at}: L{cos(kt)}=ss2+k2,L{etcos(6t)}=s1(s1)2+36,L{e3tcos(6t)}=s+3(s+3)2+36\mathcal{L} \{ \cos(kt) \} = \frac{s}{s^2 + k^2}, \quad \mathcal{L} \{ e^t \cos(6t) \} = \frac{s - 1}{(s - 1)^2 + 36}, \quad \mathcal{L} \{ e^{-3t} \cos(6t) \} = \frac{s + 3}{(s + 3)^2 + 36} Thus: L{(1et+2e3t)cos(6t)}=ss2+36s1(s1)2+36+2s+3(s+3)2+36\mathcal{L} \left\{ \left(1 - e^t + 2 e^{-3t}\right) \cos(6t) \right\} = \frac{s}{s^2 + 36} - \frac{s - 1}{(s - 1)^2 + 36} + 2 \frac{s + 3}{(s + 3)^2 + 36}


Let me know if you'd like further details or clarifications. Here are five related questions:

  1. How is the Laplace transform used to solve differential equations?
  2. What is the significance of shifting in the Laplace domain?
  3. How do inverse Laplace transforms work for solving initial value problems?
  4. What are some properties of the Laplace transform that simplify

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Math Problem Analysis

Mathematical Concepts

Laplace Transforms
Exponential Functions
Trigonometric Functions

Formulas

L{t^n e^{-at}} = n!/(s + a)^{n+1}
L{e^{at} f(t)} = F(s - a)
L{sin(kt) e^{-at}} = k / ((s + a)^2 + k^2)
L{cos(kt) e^{-at}} = (s + a) / ((s + a)^2 + k^2)

Theorems

Shifting Theorem in Laplace
Linearity of Laplace Transforms

Suitable Grade Level

Undergraduate - Engineering or Applied Mathematics