(a) L² (3x². 2 (3x² - 2x - 1) 8 (x - 3)dx (b) *(cos x) 8(x − n)dx 5 (c)( (cos x)8(x - 2π)dx

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This problem is designed to give you practice using the Dirac delta function. Evaluate the following integrals. Show your reasoning.
Transcribed Image Text:This problem is designed to give you practice using the Dirac delta function. Evaluate the following integrals. Show your reasoning.
The image contains three mathematical expressions involving integrals with a Dirac delta function. The expressions are:

(a) \(\int_{2}^{6} (3x^2 - 2x - 1) \delta(x - 3) \, dx\)

(b) \(\int_{0}^{5} (\cos x) \delta(x - \pi) \, dx\)

(c) \(\int_{0}^{5} (\cos x) \delta(x - 2\pi) \, dx\)

### Explanation:

1. **Integrals**: Each expression is an integral that evaluates a function over a specified interval. The integrals incorporate a Dirac delta function, which is a highly peaked function at a specific point.

2. **Dirac Delta Function (\(\delta(x - a)\))**:
   - Acts like a "sampling" function that picks out the value of the function at \(x = a\).
   - This means that the integral of \(f(x) \delta(x - a)\) over a range that includes \(x = a\) will be \(f(a)\).

### Evaluation of Each Integral:
- **Expression (a)**: 
  - \(\int_{2}^{6} (3x^2 - 2x - 1) \delta(x - 3) \, dx\)
  - The integral evaluates the polynomial \(3x^2 - 2x - 1\) at \(x = 3\).

- **Expression (b)**:
  - \(\int_{0}^{5} (\cos x) \delta(x - \pi) \, dx\)
  - The integral evaluates \(\cos x\) at \(x = \pi\).

- **Expression (c)**:
  - \(\int_{0}^{5} (\cos x) \delta(x - 2\pi) \, dx\)
  - The integral evaluates \(\cos x\) at \(x = 2\pi\), but since \(2\pi\) is outside the integration range [0, 5], the integral evaluates to zero.
Transcribed Image Text:The image contains three mathematical expressions involving integrals with a Dirac delta function. The expressions are: (a) \(\int_{2}^{6} (3x^2 - 2x - 1) \delta(x - 3) \, dx\) (b) \(\int_{0}^{5} (\cos x) \delta(x - \pi) \, dx\) (c) \(\int_{0}^{5} (\cos x) \delta(x - 2\pi) \, dx\) ### Explanation: 1. **Integrals**: Each expression is an integral that evaluates a function over a specified interval. The integrals incorporate a Dirac delta function, which is a highly peaked function at a specific point. 2. **Dirac Delta Function (\(\delta(x - a)\))**: - Acts like a "sampling" function that picks out the value of the function at \(x = a\). - This means that the integral of \(f(x) \delta(x - a)\) over a range that includes \(x = a\) will be \(f(a)\). ### Evaluation of Each Integral: - **Expression (a)**: - \(\int_{2}^{6} (3x^2 - 2x - 1) \delta(x - 3) \, dx\) - The integral evaluates the polynomial \(3x^2 - 2x - 1\) at \(x = 3\). - **Expression (b)**: - \(\int_{0}^{5} (\cos x) \delta(x - \pi) \, dx\) - The integral evaluates \(\cos x\) at \(x = \pi\). - **Expression (c)**: - \(\int_{0}^{5} (\cos x) \delta(x - 2\pi) \, dx\) - The integral evaluates \(\cos x\) at \(x = 2\pi\), but since \(2\pi\) is outside the integration range [0, 5], the integral evaluates to zero.
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I have use the concept property of dirac delta function 

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