Timeline for Why does the evaluation of this series fail?
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14 events
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| Jun 23, 2015 at 2:59 | history | edited | J. M.'s missing motivation♦ |
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| Aug 26, 2013 at 14:40 | answer | added | Daniel Lichtblau | timeline score: 7 | |
| Aug 26, 2013 at 13:42 | comment | added | Karl Eichenhaus | If you input the expression correctly, the series will be dependent on x. In addition, with a=1, b=2.5 the series will loss the effectiveness when x>10.5. | |
| Aug 26, 2013 at 13:30 | history | edited | Karl Eichenhaus | CC BY-SA 3.0 |
added 5 characters in body
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| Aug 26, 2013 at 13:20 | comment | added | Karl Eichenhaus | BesselJ[1,a x]BesselJ[1,b x]==a b (x^2)/4*Sum[(-1)^n*(a x/2)^(2n)*Hypergeometric2F1[-n,-1-n,2,b^2/a^2]/(n!Pochhammer[2,n]),{n,0,Infinity}]. Yes, this is the correct expression which is just evaluated by me. I thought the omitting space between the parameters would not lead to the misunderstanding of the expression. Now you can observe the above-mentioned phenomenon. The expression has no problem. The problem is the numerical evaluation of it. | |
| Aug 26, 2013 at 13:06 | comment | added | Pankaj Sejwal | so did u get what I got ? I have tried the same already. | |
| Aug 26, 2013 at 6:24 | comment | added | Pankaj Sejwal |
Hypergeometric2F1[-n,-1-n,2,b^2/a^2] has independent a,b but actually they are not independent in your supplied parameters, parameter is ax,bx it should be a x,b x.Formation of series is faulty, I suppose.
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| Aug 26, 2013 at 4:20 | comment | added | Karl Eichenhaus | @Blackbird: Thanks! The coefficient a*b*(x^2)/4 is surely irrelevant. The decisive factor of the convergence is inside the sum[...]. " If I take it as a b (x^2)/4..for all value of x I get 0.045857190997445", this is incorrect please check whether the factor (ax/2)^(2n) is missed. | |
| Aug 25, 2013 at 9:00 | comment | added | Pankaj Sejwal |
abx^2/4 is strange here and I think it doesn't affect your convergence.After putting values its a constant which does nothing to convergence or divergence of series. If I take it as a b (x^2)/4..for all value of x I get 0.045857190997445
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| S Aug 25, 2013 at 8:52 | history | edited | halirutan | CC BY-SA 3.0 |
improved formatting
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| S Aug 25, 2013 at 8:52 | history | suggested | M6299 | CC BY-SA 3.0 |
improved formatting
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| Aug 25, 2013 at 8:45 | review | First posts | |||
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| Aug 25, 2013 at 8:37 | review | Suggested edits | |||
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| Aug 25, 2013 at 8:28 | history | asked | Karl Eichenhaus | CC BY-SA 3.0 |