Difficult Integral Question: Need Help Solving LaTeX Code

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    Hard Integral
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The integral in question, ∫_{0}^{∞} (x/(x²+1)) tan(x) cos((tan(x))²) dx, does not have an elementary antiderivative, leading to challenges in finding a closed-form solution. The original source of the integral is unclear, as it was derived from a non-textbook context related to a personal anecdote. Attempts to solve it using substitutions, integration by parts, and software like Wolfram Alpha and Matlab have been unsuccessful. A suggestion was made to explore the Taylor series of the functions involved as a potential method for integration. The discussion highlights the complexity of the integral and the difficulties in solving it.
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Please help, I am not sure if you can read my latex code. A friend of mine sent this to me before her final exam, I have been trying to solve it for 3-4 days. I used some substitutions, I tried integration by parts but couldn't get a solution. I used wolfram alpha but it needs more time and for that I have to be premium. I couldn't get this solved on Matlab.
##\int_{0}^{\infty}\frac{x}{x^2+1}\tan{x}\cos{((\tan(x))^2)}dx##
 
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Where does this integral come from? It doesn't appear to have an elementary antiderivative, so do you have any reason to believe you'll be able to find a closed-form solution?
 
axmls said:
Where does this integral come from? It doesn't appear to have an elementary antiderivative, so do you have any reason to believe you'll be able to find a closed-form solution?
Well, I just asked my friend she said that she didn't actually take this from a textbook. There was a book or something a guy is talking about his high school life and then there is this integral on the page like an image or something. Well, it turns out I was just wasting my time.
Still, I wonder do you have solution of this, the one thing comes to my mind is to find Taylor series of each function and integrate.
 
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