What is the Generating Function for Bessel Functions?

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The discussion focuses on finding the generating function for Bessel functions Jn(x), specifically demonstrating that G(x,t) = ∑ from -∞ to ∞ of tn Jn(x) equals exp{(x/2)((t-T1/t))}. Participants are encouraged to use the recurrence relation Jn+1(x) + Jn-1(x) = (2n/x)Jn(x) to show that G(x,t) satisfies the differential equation (t+1/t)G(x,t) = (2t/x)∂G/∂t. The approach involves partial integration of the equation and determining an unknown function of x based on the condition that the coefficient of t^0 equals J0(x). The thread seeks guidance on whether the current setup for solving the problem is correct. The conversation emphasizes the mathematical derivation and problem-solving process related to Bessel functions.
Mark Brewer
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Homework Statement


Show that the Bessel functions Jn(x) (where n is an integer) have a very nice generating function, namely,

G(x,t) := ∑ from -∞ to ∞ of tn Jn(x) = exp {(x/2)((t-T1/t))},

Hint. Starting from the recurrence relation

Jn+1(x) + Jn-1(x) = (2n/x)Jn(x),

show that G(x,t) satisfies the differential equation (t+1/t)G(x,t) = (2t/x)∂G/∂t. Partially integrate this equation and fix the unknown function of x by the requirement that the coefficient of t0 be J0(x)

The Attempt at a Solution


This is the setup I have so far. I'm not sure if this is the correct way to go. If it is please let me know so I can continue down the pipe line.

∫xe^((x/2)(t-1/t))∂t = ∫((2t^2)/(t^2)+1)∂G

Any guidance would be helpful.
 
Thank you, Greg. You can bump this post.
 
Question: A clock's minute hand has length 4 and its hour hand has length 3. What is the distance between the tips at the moment when it is increasing most rapidly?(Putnam Exam Question) Answer: Making assumption that both the hands moves at constant angular velocities, the answer is ## \sqrt{7} .## But don't you think this assumption is somewhat doubtful and wrong?

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