Timeline for Software to decide equality between expressions involving powers and trigonometry
Current License: CC BY-SA 3.0
10 events
| when toggle format | what | by | license | comment | |
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| Jul 1, 2013 at 19:16 | history | edited | user9072 |
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| Jun 18, 2012 at 3:38 | answer | added | Robert Israel | timeline score: 2 | |
| Jun 17, 2012 at 18:46 | comment | added | Manu | Input: cos(0) = cos(0.0000000000000000001) Answer: TRUE ;-) | |
| Jun 17, 2012 at 18:41 | comment | added | Samuel Reid | You may want to try Wolfram|Alpha. I know that, for at least basic expressions, you can simply ask $f(x)=g(x)?$ and Wolfram|Alpha will output "True" or "False". | |
| Jun 17, 2012 at 18:23 | history | edited | Manu | CC BY-SA 3.0 |
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| Jun 17, 2012 at 14:37 | history | edited | Manu | CC BY-SA 3.0 |
added 118 characters in body
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| Jun 17, 2012 at 14:32 | comment | added | Manu | I do need to decide exact equality. I didn't know about the conjecture you mention, and I am editing my question to clarify. Still, is there a sound algorithm which may work on specific instances? | |
| Jun 17, 2012 at 14:11 | comment | added | Henry Cohn | I'm not sure what you mean by the "(slow) known algorithm". If you know that $A \ne B$, then just use interval arithmetic. The difficulty is getting a bound on how much precision you might need (and whether a reasonable amount suffices), but that's not an obstacle in practice. Just increase the precision if it doesn't suffice, and in practice you'll get an answer with quite reasonable precision. On the other hand, dealing with exact equality is much more algorithmically subtle, and there's no known algorithm that's even guaranteed to terminate at all without assuming Schanuel's conjecture. | |
| Jun 17, 2012 at 14:03 | answer | added | Jacques Carette | timeline score: 5 | |
| Jun 17, 2012 at 13:36 | history | asked | Manu | CC BY-SA 3.0 |