How to Compute an Integral Involving a Delta Function and Sine?

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SUMMARY

The integral ∫^{∞}_{-∞}dx (x²+a²)⁻¹δ(sin(2x)) can be computed using the property of the delta function, specifically δ[f(x)] = ∑_{k} (1/|f'(x_k)|) δ(x-x_k), where x_k are the simple zeros of the function f. In this case, f(x) = sin(2x), which has simple zeros at x = kπ/2 for k ∈ ℤ. The derivative f'(x) = 2cos(2x) must be evaluated at these points to apply the delta function property correctly.

PREREQUISITES
  • Understanding of delta functions in calculus
  • Knowledge of sine function properties and zeros
  • Familiarity with integration techniques involving distributions
  • Basic differentiation skills for evaluating derivatives
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  • Study the properties of delta functions in detail
  • Learn about the application of delta functions in integrals involving trigonometric functions
  • Explore examples of integrals involving distributions and their solutions
  • Investigate the implications of simple and multiple zeros in delta function applications
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Students in advanced calculus, mathematicians dealing with integrals involving distributions, and anyone studying the properties of delta functions in mathematical physics.

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Homework Statement


Compute ∫^{∞}_{-∞}dx (x2+a2)-1δ(sin(2x)), without calculating the resulting sum.


Homework Equations



This is a very specific integral which ,has a delta function δ operating on sin function

The Attempt at a Solution


Does anyone know this integral ? I haven't seen before any similar examples.
 
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You haven't listed all relevant equations yet:
\delta[f(x)]=\sum_{k} \frac{1}{\left |f'(x_k) \right|} \delta(x-x_k),
where x_k runs over all zeros of f, which all must be simple zeros of course in order that f'(x_k) \neq 0 for all k.
 

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