[Q] square of 'sinc function' integral

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SUMMARY

The discussion centers on solving the integral \(\int_{k_o}^0\frac{\sin^{2}(2x)}{2x^{2}}dx\) to determine the probability density associated with momentum eigenstates. The user transformed the integral using the identity \(\sin^{2}(2x) = \frac{1 - \cos(2x)}{2}\) but encountered issues with divergence due to the term \(\int_{k_o}^0\frac{1}{x^{2}}dx\). Suggestions include using series expansion for \(\cos(2x)\) to address the singular point problem and achieve convergence.

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good_phy
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Hi.

I tried to solve some problem that i should get probability density with which eigenstate of

momentum is chosen after momentum measurement by using <\varphi_{k}|\Psi>

I faced some stuck integral problem such as \int_{k_o}^0\frac{sin^{2}(2x)}{2x^{2}}dx

I transformed sin^{2}(2x) = \frac{1 - cos(2x)}{2} so i obtained \int_{k_o}^0\frac{1-cos(2x)}{2x^{2}}dx but i don't know next step because, \int_{k_o}^0\frac{1}{x^2}dx go up to infinity,diverse.

i tried to do partial integral such as \int udv = uv - \int vdu but encountered same problem.

How can i overcome this singular point problem? i convinced that \int_{k_o}^0\frac{sin^{2}(2x)}{2x^{2}}dx

should be solved to convegence because graphic of \frac{sin^{2}(2x)}{2x^{2}}.

Please help me and give me an answer.
 
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i think you can try to write the cos as a series form.
P.S. the third formula in your statements seems...
 

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