L{y(t)} = (s/((s+36)(s^2+36)))+((8+7s)/(s^2+36)) c. Take the inverse Laplace transform of both sides of the previous equation to solve for y(t). y(t) = ((99/74)sin(6t))-((1/37)e^(-36t))+((260/37) cos(6t))

Advanced Engineering Mathematics
10th Edition
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Author:Erwin Kreyszig
Publisher:Erwin Kreyszig
Chapter2: Second-order Linear Odes
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Here is the problem. Why is my third answer wrong?

**Results for this submission**

| Entered                                                                                                         | Answer Preview                                                                                          | Result     | Message                                                  |
|-----------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------|------------|----------------------------------------------------------|
| (s^2)*Y(s)-7*s-8+36*Y(s)                                                                                        | \( s^2Y(s) - 7s - 8 + 36Y(s) \)                                                                        | correct    |                                                          |
| s/[(s^2)+36]                                                                                                    | \( \frac{s}{s^2 + 36} \)                                                                               | correct    |                                                          |
| (s/[(s+36)*[(s^2)+36]])+[(8+7*s)/[(s^2)+36]]                                                                   | \( \frac{s}{(s + 36)(s^2 + 36)} + \frac{8 + 7s}{s^2 + 36} \)                                          | correct    |                                                          |
| (99/74)*sin(6*t)-(1/37)*[e^(-36*t)]+(260/37)*cos(6*t)                                                           | \( \frac{99}{74}\sin(6t) - \frac{1}{37}e^{-36t} + \frac{260}{37}\cos(6t) \)                             | incorrect | This answer is equivalent to the one you just submitted. |

**Explanation of Graphs or Diagrams:**

There are no graphs or diagrams present. The table shows the entered mathematical expressions, the expected answer previews, the results indicating whether each submission was correct or incorrect, and any messages related to the entries.
Transcribed Image Text:**Results for this submission** | Entered | Answer Preview | Result | Message | |-----------------------------------------------------------------------------------------------------------------|--------------------------------------------------------------------------------------------------------|------------|----------------------------------------------------------| | (s^2)*Y(s)-7*s-8+36*Y(s) | \( s^2Y(s) - 7s - 8 + 36Y(s) \) | correct | | | s/[(s^2)+36] | \( \frac{s}{s^2 + 36} \) | correct | | | (s/[(s+36)*[(s^2)+36]])+[(8+7*s)/[(s^2)+36]] | \( \frac{s}{(s + 36)(s^2 + 36)} + \frac{8 + 7s}{s^2 + 36} \) | correct | | | (99/74)*sin(6*t)-(1/37)*[e^(-36*t)]+(260/37)*cos(6*t) | \( \frac{99}{74}\sin(6t) - \frac{1}{37}e^{-36t} + \frac{260}{37}\cos(6t) \) | incorrect | This answer is equivalent to the one you just submitted. | **Explanation of Graphs or Diagrams:** There are no graphs or diagrams present. The table shows the entered mathematical expressions, the expected answer previews, the results indicating whether each submission was correct or incorrect, and any messages related to the entries.
Consider the initial value problem

\[
y'' + 36y = \cos(6t), \quad y(0) = 7, \quad y'(0) = 8.
\]

a. Take the Laplace transform of both sides of the given differential equation to create the corresponding algebraic equation. Denote the Laplace transform of \(y(t)\) by \(Y(s)\). Do not move any terms from one side of the equation to the other (until you get to part (b) below).

\[
(s^2Y(s)) - 7s - 8 + 36Y(s) = \frac{s}{s^2 + 36}
\]

b. Solve your equation for \(Y(s)\).

\[
Y(s) = \mathcal{L}\{y(t)\} = \left(\frac{s}{((s+36)(s^2+36))}\right) + \left(\frac{(8+7s)}{(s^2+36)}\right)
\]

c. Take the inverse Laplace transform of both sides of the previous equation to solve for \(y(t)\).

\[
y(t) = \left(\frac{99}{74}\sin(6t)\right) - \left(\frac{1}{37}e^{-36t}\right) + \left(\frac{260}{37}\cos(6t)\right)
\]
Transcribed Image Text:Consider the initial value problem \[ y'' + 36y = \cos(6t), \quad y(0) = 7, \quad y'(0) = 8. \] a. Take the Laplace transform of both sides of the given differential equation to create the corresponding algebraic equation. Denote the Laplace transform of \(y(t)\) by \(Y(s)\). Do not move any terms from one side of the equation to the other (until you get to part (b) below). \[ (s^2Y(s)) - 7s - 8 + 36Y(s) = \frac{s}{s^2 + 36} \] b. Solve your equation for \(Y(s)\). \[ Y(s) = \mathcal{L}\{y(t)\} = \left(\frac{s}{((s+36)(s^2+36))}\right) + \left(\frac{(8+7s)}{(s^2+36)}\right) \] c. Take the inverse Laplace transform of both sides of the previous equation to solve for \(y(t)\). \[ y(t) = \left(\frac{99}{74}\sin(6t)\right) - \left(\frac{1}{37}e^{-36t}\right) + \left(\frac{260}{37}\cos(6t)\right) \]
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