https://www.explainxkcd.com/wiki/api.php?action=feedcontributions&feedformat=atom&user=Gintsexplain xkcd - User contributions [en]2026-04-15T21:14:49ZUser contributionsMediaWiki 1.30.0https://www.explainxkcd.com/wiki/index.php?title=2070:_Trig_Identities&diff=1657292070: Trig Identities2018-11-09T19:22:21Z<p>Gints: Minor grammar fix</p>
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<div>{{comic<br />
| number = 2070<br />
| date = November 9, 2018<br />
| title = Trig Identities<br />
| image = trig_identities.png<br />
| titletext = ARCTANGENT THETA = ENCHANT AT TARGET<br />
}}<br />
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==Explanation==<br />
{{incomplete|Please only mention here why this explanation isn't complete. Do NOT delete this tag too soon.}}<br />
This comic shows several real and fictitious trigonometric identities. Most of the identities past the second line are "derived" by applying algebraic methods to the letters in the trig functions, which violates the rules of math, since the trig functions are operators and not variables.<br />
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The first line are well known trigonometric functions. The second line contains the lesser known reciprocals of the trigonometric functions in the first line. The following identities are made up and are increasing in absurdity. The comic reflects on the confusion one gets when working more intensely with these identities, since there are a lot of hidden dependencies between them.<br />
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==Transcript==<br />
{{incomplete transcript|Do NOT delete this tag too soon.}}<br />
:[Inside a single frame comic a right-angled triangle is shown. The short edges are labeled "a" and "b" respectively and the long edge has a "c". All angles are marked, the right angle by a square and the both others by an arc. One arc is labeled by the Greek symbol theta.]<br />
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:[Trigonometric functions on the marked angle theta in relation to "a", "b", and many more not depicted other variables are shown:]<br />
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:[Caption below the frame:]<br />
:Key trigonometric identities<br />
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{{comic discussion}}<br />
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[[Category:Math]]</div>Gints