https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&user=141.101.81.206&feedformat=atomexplain xkcd - User contributions [en]2024-03-28T17:48:52ZUser contributionsMediaWiki 1.30.0https://www.explainxkcd.com/wiki/index.php?title=Talk:1376:_Jump&diff=68813Talk:1376: Jump2014-06-04T10:11:03Z<p>141.101.81.206: </p>
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<div>I guess the "G L I D E" could be a reference to Fight Club scene. The one with the Penguin during one of Tylor's support groups. [[Special:Contributions/141.101.88.214|141.101.88.214]] 09:03, 2 June 2014 (UTC)<br />
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The statement someone added, saying that if gravity had ceased he'd leave the earth's orbit due to the lack of the Sun's gravity, is incorrect; the Sun's gravitational force at the Earth is far lower than the Earth's gravity, so the loss would not be noticeable until well after he'd ended up in space. As such, I removed that statement. {{unsigned ip|108.162.219.15}}<br />
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I have always wondered why flying/gliding dreams seem to be universal for humans, not to mention all those dreams where you are viewing the world from an elevated position, I.e. near the ceiling or up in a cloud. After all, people do not fly, none of us have ever flown, none of our ancestors have ever flown, so whence all these flying dreams? Not sure if our arboreal ancestors were ever nimble enough to "fly" through the trees, but it would have been a long way back. [[Special:Contributions/108.162.245.117|108.162.245.117]] 12:24, 2 June 2014 (UTC)<br />
:In the last century a lot of us have flown (assisted). Of course, our obsession with the idea of flying is much older than our actual taking to the skies, by several millennia. (Unless, "Aliens!") But, could it simply be because all that there was to see at night was the sky? If you woke up in the middle of the night, stared at the stars for a few minutes and went back to sleep, would that make you want to travel upwards towards them in your dreams? [[Special:Contributions/103.22.201.239|103.22.201.239]] 05:51, 3 June 2014 (UTC)<br />
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Why is "GLIDE" in all-caps in the transcript? The whole comic is in all-caps. [[Special:Contributions/108.162.237.218|108.162.237.218]] 12:32, 2 June 2014 (UTC)<br />
:perhaps because the letters are separated out(?)... it would look a little weird to me for them not to be all caps - all XKCD comics are in all caps (it's the font), so that's not a differentiating factor -- [[User:Brettpeirce|Brettpeirce]] ([[User talk:Brettpeirce|talk]]) 13:11, 2 June 2014 (UTC)<br />
:Correct - since it is not a single word but individual words they should all be capital. All sentences here in the transcripts are written with capital letters - so as these letters each represents an individual sentence they should begin with a capital letter. [[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 13:54, 2 June 2014 (UTC)<br />
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It's a dream of every wolfenstein enemy-territory player ;-) Theres a bug where you can get a lot of speed be running and jumping around.<br />
[[Special:Contributions/108.162.219.54|108.162.219.54]] 15:02, 2 June 2014 (UTC)<br />
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If Cueball isn't following the Earth's curvature, he could end up in Valinor (if he's travelling westward). —[[User:TobyBartels|TobyBartels]] ([[User talk:TobyBartels|talk]]) 19:59, 2 June 2014 (UTC)<br />
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I'm not sure what's happening at the "Recent Changes" link in the left sidebar, but it stalls halfway thru loading and then locks up 105% of my Mac's CPU. Could it be a super super long amount of data, and the sysops need to snip that to a more manageable level? [[User:Jimmbo|Jimmbo]] ([[User talk:Jimmbo|talk]]) 20:22, 2 June 2014 (UTC)<br />
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Is it relevant to talk about Newton's ludicrously high mountain experiment (>1000 km) => 7300 m/s? Why not simply state that you have to go around 7900 m/s at sea level to maintain orbit (if no other forces are acting on you) [[Special:Contributions/141.101.81.206|141.101.81.206]] 21:30, 3 June 2014 (UTC)<br />
:Everybody knows that this slow gliding would only work in a dream. The correct speed at sea level would be 7.91 km/s and this comic isn't talking about this high velocities anyway. --[[User:Dgbrt|Dgbrt]] ([[User talk:Dgbrt|talk]]) 22:22, 3 June 2014 (UTC)<br />
::True enough [[Special:Contributions/141.101.81.206|141.101.81.206]] 10:11, 4 June 2014 (UTC)<br />
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There are similarities to the story of flying Robert http://www.sagen.at/texte/maerchen/maerchen_deutschland/hoffmann/fliegender_robert_1.html , a story from "der Struwwelpeter", german classic for children. [[Special:Contributions/141.101.97.220|141.101.97.220]] 07:08, 4 June 2014 (UTC)<br />
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I used to have trouble landing the first few times too, but I got better soon. [[Special:Contributions/141.101.97.206|141.101.97.206]] 09:47, 4 June 2014 (UTC)</div>141.101.81.206https://www.explainxkcd.com/wiki/index.php?title=Talk:1376:_Jump&diff=68765Talk:1376: Jump2014-06-03T21:30:14Z<p>141.101.81.206: </p>
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<div>I guess the "G L I D E" could be a reference to Fight Club scene. The one with the Penguin during one of Tylor's support groups. [[Special:Contributions/141.101.88.214|141.101.88.214]] 09:03, 2 June 2014 (UTC)<br />
<br />
The statement someone added, saying that if gravity had ceased he'd leave the earth's orbit due to the lack of the Sun's gravity, is incorrect; the Sun's gravitational force at the Earth is far lower than the Earth's gravity, so the loss would not be noticeable until well after he'd ended up in space. As such, I removed that statement. {{unsigned ip|108.162.219.15}}<br />
<br />
I have always wondered why flying/gliding dreams seem to be universal for humans, not to mention all those dreams where you are viewing the world from an elevated position, I.e. near the ceiling or up in a cloud. After all, people do not fly, none of us have ever flown, none of our ancestors have ever flown, so whence all these flying dreams? Not sure if our arboreal ancestors were ever nimble enough to "fly" through the trees, but it would have been a long way back. [[Special:Contributions/108.162.245.117|108.162.245.117]] 12:24, 2 June 2014 (UTC)<br />
:In the last century a lot of us have flown (assisted). Of course, our obsession with the idea of flying is much older than our actual taking to the skies, by several millennia. (Unless, "Aliens!") But, could it simply be because all that there was to see at night was the sky? If you woke up in the middle of the night, stared at the stars for a few minutes and went back to sleep, would that make you want to travel upwards towards them in your dreams? [[Special:Contributions/103.22.201.239|103.22.201.239]] 05:51, 3 June 2014 (UTC)<br />
<br />
Why is "GLIDE" in all-caps in the transcript? The whole comic is in all-caps. [[Special:Contributions/108.162.237.218|108.162.237.218]] 12:32, 2 June 2014 (UTC)<br />
:perhaps because the letters are separated out(?)... it would look a little weird to me for them not to be all caps - all XKCD comics are in all caps (it's the font), so that's not a differentiating factor -- [[User:Brettpeirce|Brettpeirce]] ([[User talk:Brettpeirce|talk]]) 13:11, 2 June 2014 (UTC)<br />
:Correct - since it is not a single word but individual words they should all be capital. All sentences here in the transcripts are written with capital letters - so as these letters each represents an individual sentence they should begin with a capital letter. [[User:Kynde|Kynde]] ([[User talk:Kynde|talk]]) 13:54, 2 June 2014 (UTC)<br />
<br />
It's a dream of every wolfenstein enemy-territory player ;-) Theres a bug where you can get a lot of speed be running and jumping around.<br />
[[Special:Contributions/108.162.219.54|108.162.219.54]] 15:02, 2 June 2014 (UTC)<br />
<br />
If Cueball isn't following the Earth's curvature, he could end up in Valinor (if he's travelling westward). —[[User:TobyBartels|TobyBartels]] ([[User talk:TobyBartels|talk]]) 19:59, 2 June 2014 (UTC)<br />
<br />
I'm not sure what's happening at the "Recent Changes" link in the left sidebar, but it stalls halfway thru loading and then locks up 105% of my Mac's CPU. Could it be a super super long amount of data, and the sysops need to snip that to a more manageable level? [[User:Jimmbo|Jimmbo]] ([[User talk:Jimmbo|talk]]) 20:22, 2 June 2014 (UTC)<br />
<br />
Is it relevant to talk about Newton's ludicrously high mountain experiment (>1000 km) => 7300 m/s? Why not simply state that you have to go around 7900 m/s at sea level to maintain orbit (if no other forces are acting on you) [[Special:Contributions/141.101.81.206|141.101.81.206]] 21:30, 3 June 2014 (UTC)</div>141.101.81.206https://www.explainxkcd.com/wiki/index.php?title=1201:_Integration_by_Parts&diff=623931201: Integration by Parts2014-03-10T20:39:15Z<p>141.101.81.206: /* Explanation */ The antiderivative in a definite integral could be "any antiderivative", hence the constant could be added but does not have to be added.</p>
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<div>{{comic<br />
| number = 1201<br />
| date = April 19, 2013<br />
| title = Integration by Parts<br />
| image = integration by parts.png<br />
| titletext = If you can manage to choose u and v such that u = v = x, then the answer is just (1/2)x^2, which is easy to remember. Oh, and add a '+C' or you'll get yelled at.<br />
}}<br />
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==Explanation==<br />
{{w|Integration by parts}} is an integration strategy that is used to evaluate difficult integrals by trying to find simpler integrals derived from the original. It is commonly a source of confusion or irritation for students when they first learn it, due to the fact that there is really no way to accurately predict the proper u/dv separation just by looking at an integral. Integration by parts requires patience, trial and error, and experience.<br />
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Randall shows a somewhat complicated math problem and, in an attempt to "help", simplifies it into a more compact integral. This is the first part of performing integration by parts, which involves the guessing. Having gotten it into integration by parts format, he then leaves without describing the actual solution. The general integral '''''∫'''(u dv)dx'' is equal to ''uv - '''∫'''(v du)dx'', and this is the more tedious part of the math and where problems will arise if you picked the wrong u and dv at the beginning. The narrator makes a point of leaving here, so we can't ask for help or complain if the choice of u and dv was wrong.<br />
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In the title text, he points out that if the integral of x can be divided so that u = x and dv = dx (implying v = x), then it leads to the result (1/2)x^2 (implying the original integral was just ∫x dx, and not needing integration by parts in the first place). Mathematics teachers and extreme math geeks will also cringe at this answer, however, since an indefinite integral requires an integration constant. The correct answer is actually (1/2)x^2 + C, as Randall hints. The + C symbolizes that an integral can be shifted vertically any number (a constant) and still get the same answer. Definite integrals (which specify a specific range that they're valid on) do not have to have the added constant.<br />
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==Transcript==<br />
:A Guide to<br />
:Integration by Parts:<br />
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:Given a problem of the form:<br />
::∫f(x)g(x)dx=?<br />
:Choose variables u and v such that<br />
::u=f(x)<br />
::dv=g(x)dx<br />
:Now the expression becomes:<br />
::∫udv=?<br />
:Which ''definitely'' looks easier.<br />
:Anyway, I gotta run.<br />
:But good luck!<br />
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==Trivia==<br />
*[[569: Borders]] makes a subtle reference to integration by parts (the name of the kingdom).<br />
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{{comic discussion}}<br />
[[Category:Math]]<br />
[[Category:Sarcasm]]</div>141.101.81.206