Timeline for DSolve to obtain a tanh solution
Current License: CC BY-SA 4.0
10 events
| when toggle format | what | by | license | comment | |
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| May 10, 2021 at 16:01 | history | edited | Brad | CC BY-SA 4.0 |
correcting incorrect screenshot
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| May 10, 2021 at 15:59 | comment | added | Brad | Whoops... the mistake was fully mine in there then; I've made another typo somewhere, but it's only an overall factor or so out... Regardless, after your happy reminder that MMA likes to solve equations in a particular form. I'll remove the image; good spot, thank you! | |
| May 10, 2021 at 15:55 | comment | added | Michael E2 | Actually I just copied the equation from the Maple output (1), so the error originates there, which was really my point. Or rather: the Maple code and Mathematica code do not seem equivalent. | |
| May 10, 2021 at 15:34 | vote | accept | Brad | ||
| May 10, 2021 at 15:32 | comment | added | Brad |
Dear Michael - thanks for your response. There's a small typo in your equation above (I see you've basically taken the square root of each side but have omitted the square roots of the 1/2 factor and xi^2). This is then equivalent to what has been fed into Maple, and is therefore the same as the third and final ZFeqn above. However, this answers my question of why the previous attempts were not finding the solutions that I expected - I forgot that MMA does not like equations of the type (f'[x])^2 = ...!
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| May 10, 2021 at 15:17 | answer | added | Alexei Boulbitch | timeline score: 7 | |
| May 10, 2021 at 15:11 | comment | added | Michael E2 |
Mathematica reproduces the Maple result thus: DSolve[xi^2*(f'[x]) + (1/2)*f[x]^2 - 1/2 == 0, f[x], x] // FullSimplify. The ODE you fed Maple does not seem equivalent to the first ZFeqn above, but maybe I'm blind to some obvious transformation.
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| May 10, 2021 at 14:08 | answer | added | Ulrich Neumann | timeline score: 3 | |
| May 10, 2021 at 14:00 | history | edited | Brad | CC BY-SA 4.0 |
maple description
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| May 10, 2021 at 13:21 | history | asked | Brad | CC BY-SA 4.0 |