<?xml version="1.0" encoding="UTF-8"?><rss xmlns:dc="http://purl.org/dc/elements/1.1/" xmlns:content="http://purl.org/rss/1.0/modules/content/" xmlns:atom="http://www.w3.org/2005/Atom" version="2.0"><channel><title><![CDATA[RSS Feed]]></title><description><![CDATA[RSS Feed]]></description><link>http://direct.ecency.com</link><image><url>http://direct.ecency.com/logo512.png</url><title>RSS Feed</title><link>http://direct.ecency.com</link></image><generator>RSS for Node</generator><lastBuildDate>Tue, 14 Apr 2026 05:28:57 GMT</lastBuildDate><atom:link href="http://direct.ecency.com/created/trigonometry/rss.xml" rel="self" type="application/rss+xml"/><item><title><![CDATA[Problems Plus 3: Line and Surface of Two Intersecting Planes]]></title><description><![CDATA[In this video I determine the symmetric equations of a line at the intersection of two planes. I then find out that when the equations of the plane vary, the line sweeps out a circular hyperboloid of one]]></description><link>http://direct.ecency.com/hive-147010/@mes/problems-plus-3-line-and-surface-of-two-intersecting-planes</link><guid isPermaLink="true">http://direct.ecency.com/hive-147010/@mes/problems-plus-3-line-and-surface-of-two-intersecting-planes</guid><category><![CDATA[hive-147010]]></category><dc:creator><![CDATA[mes]]></dc:creator><pubDate>Sat, 05 Oct 2024 04:08:57 GMT</pubDate><enclosure url="https://images.ecency.com/p/JLypLpqVPBaKaRaoubFyzF8ART61na2a8Kq4PUGKQePjzVsqLff6fgyHjbkiPEuN5hx5dMQDMvHDpdYzyDrr5EKMqfKXDqH6jGfGnufzQBCuVqom6hq6mDFJoYKxG83Axeq7qcWtUycJxupDb74q1jhdDWtZaJW5NFKWykFvKnakKn5jevCHQ6hZc89PeiDXKM?format=match&amp;mode=fit" length="0" type="false"/></item><item><title><![CDATA[An Introduction To Trigonometric Ratios & SOH CAH TOA]]></title><description><![CDATA[Hi there. In this math post I provide an introduction to trigonometric ratios of right angled triangles. I also cover the useful memory aid SOH CAH TOA and its usage.   Topics Right Angle Triangles]]></description><link>http://direct.ecency.com/hive-163521/@dkmathstats/an-introduction-to-trigonometric-ratios</link><guid isPermaLink="true">http://direct.ecency.com/hive-163521/@dkmathstats/an-introduction-to-trigonometric-ratios</guid><category><![CDATA[hive-163521]]></category><dc:creator><![CDATA[dkmathstats]]></dc:creator><pubDate>Sat, 28 Sep 2024 12:32:45 GMT</pubDate><enclosure url="https://images.ecency.com/p/2FFvzA2zeqoVPgRCnRzbu6rj6tCWHWVCA9ZaKB4Zpygwh1BoTuMr9X2gtff81Jd31xPfzuxGcPqQz9yMg684oYr6kMxVKBoZqxSrZogr6w18aPGiLPnyFucMjU6WA?format=match&amp;mode=fit" length="0" type="false"/></item><item><title><![CDATA[Example 2: Approximating sin(x) with Taylor Polynomials and Calculating its Error]]></title><description><![CDATA[In this video I go over a very in-depth video exploring the trigonometric sine function, its Taylor polynomials approximation, and its associated error.]]></description><link>http://direct.ecency.com/hive-147010/@mes/example-2-approximating-sin-x-with-taylor-polynomials-and-calculating-its-error</link><guid isPermaLink="true">http://direct.ecency.com/hive-147010/@mes/example-2-approximating-sin-x-with-taylor-polynomials-and-calculating-its-error</guid><category><![CDATA[hive-147010]]></category><dc:creator><![CDATA[mes]]></dc:creator><pubDate>Fri, 30 Aug 2024 03:05:12 GMT</pubDate><enclosure url="https://images.ecency.com/p/2N61tyyncFaFVtpM8q6r7eyQFvUiqNpQu6o2Yd65xmPkkdqXi9SFbNdkWR7cyprPzDnc5ftw5bmTG4cPkZSdZMT2GeXPELMrKZEjHkgFMYhTtu4TTF1ZsJAwU8rkU5tBAorHrjMCTPTu?format=match&amp;mode=fit" length="0" type="false"/></item><item><title><![CDATA[Example 2: Approximating sin(x) with Taylor Polynomials and Calculating its Error]]></title><description><![CDATA[In this video I go over a very in-depth video exploring the trigonometric sine function, its Taylor polynomials approximation, and its associated error. The Maclaurin polynomial (Taylor series centered]]></description><link>http://direct.ecency.com/hive-128780/@mes/yisooxwc</link><guid isPermaLink="true">http://direct.ecency.com/hive-128780/@mes/yisooxwc</guid><category><![CDATA[hive-128780]]></category><dc:creator><![CDATA[mes]]></dc:creator><pubDate>Fri, 30 Aug 2024 02:25:06 GMT</pubDate><enclosure url="https://images.ecency.com/p/99pyU5Ga1kwr5bsMXthzYLbcngN4W2P8NtU9TWTdHC3HaQbjuuRfHesJoVtLzU947mQsbRYUk3MWSHFkuW2Pn1t3xTJt14HiNRo4MThXwd5Y7EcaWZ35evfQo9YVLQcG4W?format=match&amp;mode=fit" length="0" type="false"/></item><item><title><![CDATA[Trigonometry: Sine, Cosine and Tan Functions]]></title><description><![CDATA[▶️Watch on 3Speak - Odysee - BitChute - Rumble - YouTube - PDF notes This video shows a brief introduction to the wonderful world of trigonometry and defines the functions Sine, Cosine and Tan. Also, how]]></description><link>http://direct.ecency.com/hive-128780/@mes/trigonometry-sine-cosein-tan</link><guid isPermaLink="true">http://direct.ecency.com/hive-128780/@mes/trigonometry-sine-cosein-tan</guid><category><![CDATA[hive-128780]]></category><dc:creator><![CDATA[mes]]></dc:creator><pubDate>Mon, 22 Apr 2024 06:13:57 GMT</pubDate><enclosure url="https://images.ecency.com/p/S5Eokt4BcQdk7EHeT1aYjzebg2hC7hkthT45eB6eVMHzXuyrTmqiLRHAC9RhzDuVN9QrYMk?format=match&amp;mode=fit" length="0" type="false"/></item><item><title><![CDATA[Exact Trigonometry Ratios Part 1: 0, 30, 45, 60, and 90 Degrees]]></title><description><![CDATA[▶️Watch on 3Speak - Odysee - BitChute - Rumble - DTube - YouTube - PDF notes This is a very useful on showing some easy ways of deriving how to get the exact Trig Ratios for 0, 30, 45, 60 and 90 degrees.]]></description><link>http://direct.ecency.com/hive-128780/@mes/exact-trigonometry-ratios-part-</link><guid isPermaLink="true">http://direct.ecency.com/hive-128780/@mes/exact-trigonometry-ratios-part-</guid><category><![CDATA[hive-128780]]></category><dc:creator><![CDATA[mes]]></dc:creator><pubDate>Mon, 26 Feb 2024 22:52:03 GMT</pubDate><enclosure url="https://images.ecency.com/p/S5Eokt4BcQdk7EHeT1aYjzebg2hC7hkthT45eKbvUSytD6Ses5pj8HhNKYZKQHXiayGz5FL?format=match&amp;mode=fit" length="0" type="false"/></item><item><title><![CDATA[Exact Trigonometric Ratios Part 2: Examples]]></title><description><![CDATA[▶️Watch on 3Speak - Odysee - BitChute - Rumble - DTube - YouTube - PDF notes This video provides some examples to further explain trigonometric functions which were discussed in my previous videos. View]]></description><link>http://direct.ecency.com/hive-128780/@mes/exact-trigonometric-ratios-part-2-examples</link><guid isPermaLink="true">http://direct.ecency.com/hive-128780/@mes/exact-trigonometric-ratios-part-2-examples</guid><category><![CDATA[hive-128780]]></category><dc:creator><![CDATA[mes]]></dc:creator><pubDate>Thu, 15 Feb 2024 17:54:42 GMT</pubDate><enclosure url="https://images.ecency.com/p/S5Eokt4BcQdk7EHeT1aYjzebg2hC7hkthT45eN1LBE4YLGi4LrLGiMKoBFNnuGh8khcSE6S?format=match&amp;mode=fit" length="0" type="false"/></item><item><title><![CDATA[Trigonometry Identity: Proof that sin^2(x) + cos^2(x) = 1]]></title><description><![CDATA[▶️Watch on 3Speak - Odysee - BitChute - Rumble - DTube - YouTube - PDF notes A simple proof of the very important and useful trigonometry Identity sin2(x) + cos2(x) = 1 is shown. Also the notation for]]></description><link>http://direct.ecency.com/hive-128780/@mes/trigonometry-identity-proof-that-sin2x-cos2x-1</link><guid isPermaLink="true">http://direct.ecency.com/hive-128780/@mes/trigonometry-identity-proof-that-sin2x-cos2x-1</guid><category><![CDATA[hive-128780]]></category><dc:creator><![CDATA[mes]]></dc:creator><pubDate>Sun, 04 Feb 2024 16:42:42 GMT</pubDate><enclosure url="https://images.ecency.com/p/S5Eokt4BcQdk7EHeT1aYjzebg2hC7hkthT45eLi2iEeZaEEKmgo41sEtPUX5QotKimtvvHU?format=match&amp;mode=fit" length="0" type="false"/></item><item><title><![CDATA[Sum Of Angle Formulas For Sine & Cosine]]></title><description><![CDATA[Hi there. In this math education post I cover the topic of sum of angle formulas for sine and cosine. This topic is a part of the trigonometry section of mathematics. You normally find this in high school]]></description><link>http://direct.ecency.com/hive-163521/@dkmathstats/sum-of-angle-formulas-for-sine-and-cosine</link><guid isPermaLink="true">http://direct.ecency.com/hive-163521/@dkmathstats/sum-of-angle-formulas-for-sine-and-cosine</guid><category><![CDATA[hive-163521]]></category><dc:creator><![CDATA[dkmathstats]]></dc:creator><pubDate>Fri, 05 Jan 2024 21:36:18 GMT</pubDate><enclosure url="https://images.ecency.com/p/3HaJVw3AYyXB6DfixgRs18hVdqwooFTPVzUC54j2BtdmZYWemLcn2AiKJ5j8jVW6xji46Es5nq4LADzwRJNFdncYAYFdFziHh5S6Yvr?format=match&amp;mode=fit" length="0" type="false"/></item><item><title><![CDATA[Double Angle Formula For Sine]]></title><description><![CDATA[Hi there. In this math post I cover the double angle formula for the sine trigonometric function. I cover the base formula, a rearranged formula and cover some examples. It is assumed that the reader is]]></description><link>http://direct.ecency.com/hive-163521/@dkmathstats/double-angle-formula-for-sine</link><guid isPermaLink="true">http://direct.ecency.com/hive-163521/@dkmathstats/double-angle-formula-for-sine</guid><category><![CDATA[hive-163521]]></category><dc:creator><![CDATA[dkmathstats]]></dc:creator><pubDate>Sun, 31 Dec 2023 05:01:09 GMT</pubDate><enclosure url="https://images.ecency.com/p/X37EMQ9WSwsKQG7nhCXMsgXxUQHwtJm4rGgDFSP27G8Nse5UibYZEMTHkEw9gzRWzDTmACL89eVeUpVHJBgXNs5p2dnXdZ3oaNWjx?format=match&amp;mode=fit" length="0" type="false"/></item><item><title><![CDATA[Trigonometry Graphing: Sin, Cos, Tan Functions]]></title><description><![CDATA[A simple introduction to graphing Sine, Cosine and Tan Functions is shown. These functions are cyclical and are used in many real world applications so it is very important to understand there graphs.]]></description><link>http://direct.ecency.com/hive-128780/@mes/trigonometry-graphing-sin-cos-tan-functions</link><guid isPermaLink="true">http://direct.ecency.com/hive-128780/@mes/trigonometry-graphing-sin-cos-tan-functions</guid><category><![CDATA[hive-128780]]></category><dc:creator><![CDATA[mes]]></dc:creator><pubDate>Tue, 31 Oct 2023 20:11:36 GMT</pubDate><enclosure url="https://images.ecency.com/p/S5Eokt4BcQdk7EHeT1aYjzebg2hC7hkthT45eKaZE8aiFJe6KqTdYwi9zdqj93twcoZnBVY?format=match&amp;mode=fit" length="0" type="false"/></item><item><title><![CDATA[Problems Plus 8: Trigonometric Formula and Sum of Series Involving Inverse Cotangent]]></title><description><![CDATA[In this video I derive a similar formula as in Problem 7 but this time use arccot or inverse cotangent. I then use that formula, as well as the useful method of the Telescoping Sum, to determine the sum]]></description><link>http://direct.ecency.com/hive-128780/@mes/jahsuyos</link><guid isPermaLink="true">http://direct.ecency.com/hive-128780/@mes/jahsuyos</guid><category><![CDATA[hive-128780]]></category><dc:creator><![CDATA[mes]]></dc:creator><pubDate>Sat, 16 Sep 2023 05:37:03 GMT</pubDate><enclosure url="https://images.ecency.com/p/99pyU5Ga1kwr5bsMXthzYLbcngN4W2P8NtU9TWTdHC3HaQbjuuRfHesJoVxZMEKV6awnqcarW9CodxLcouFv174vbfJNiTjPnZ3a8xA3o4rBzxffk2CJUSp6eBDPW6C6bY?format=match&amp;mode=fit" length="0" type="false"/></item><item><title><![CDATA[Problems Plus 7: Calculating π Using Inverse Tangent Maclaurin Series]]></title><description><![CDATA[In this video I go over a very long problem that involves first determining several arctan formulas and then using them to determine the value of the π up to 7 decimal places. One such formula is named]]></description><link>http://direct.ecency.com/hive-128780/@mes/userndoe</link><guid isPermaLink="true">http://direct.ecency.com/hive-128780/@mes/userndoe</guid><category><![CDATA[hive-128780]]></category><dc:creator><![CDATA[mes]]></dc:creator><pubDate>Fri, 15 Sep 2023 06:22:06 GMT</pubDate><enclosure url="https://images.ecency.com/p/99pyU5Ga1kwr5bsMXthzYLbcngN4W2P8NtU9TWTdHC3HaQbjuuRfHesJoVyeYHJmEkZhPyXeJnDPNKYViFeCRLbu7LUYsYvjpDboHGEWBWY4L7WZSHch7mk1ZhYWgAH9Sv?format=match&amp;mode=fit" length="0" type="false"/></item><item><title><![CDATA[Problems Plus 4: Limit of the Angle of a Spiraling Triangle Sequence]]></title><description><![CDATA[In this video I go over a sequence which involves rotating triangles around a point and determining the limit of the inner angle of the triangles. To solve this I first use the Pythagorean Theorem to determine]]></description><link>http://direct.ecency.com/hive-128780/@mes/bxjpgicn</link><guid isPermaLink="true">http://direct.ecency.com/hive-128780/@mes/bxjpgicn</guid><category><![CDATA[hive-128780]]></category><dc:creator><![CDATA[mes]]></dc:creator><pubDate>Fri, 01 Sep 2023 03:51:03 GMT</pubDate><enclosure url="https://images.ecency.com/p/99pyU5Ga1kwr5bsMXthzYLbcngN4W2P8NtU9TWTdHC3HaQbjuuRfHesJoVyNdqpdh7heE2nn3XrAC5rG8fLXK7tfeHeh5Z7Ep1bmaKeg3FhQTMMPRFfZ9drKwSBEaZZioY?format=match&amp;mode=fit" length="0" type="false"/></item><item><title><![CDATA[Problems Plus 3: Trigonometric Identity and Sum of Infinite Series]]></title><description><![CDATA[In this video I go over a two-part problem that involves proving a trigonometric identity and then using that identity to find the sum of an infinite series. The trig identity involves a half angle tangent]]></description><link>http://direct.ecency.com/hive-128780/@mes/vpycmngc</link><guid isPermaLink="true">http://direct.ecency.com/hive-128780/@mes/vpycmngc</guid><category><![CDATA[hive-128780]]></category><dc:creator><![CDATA[mes]]></dc:creator><pubDate>Thu, 31 Aug 2023 05:51:03 GMT</pubDate><enclosure url="https://images.ecency.com/p/99pyU5Ga1kwr5bsMXthzYLbcngN4W2P8NtU9TWTdHC3HaQbjuuRfHesJoVybfVFoaiub3ubGi4Kw1TiH1faC5EkJYhBQkSjb1Wi4o4gtNywhnPvJCDfyG6rTpQyeFVVWEA?format=match&amp;mode=fit" length="0" type="false"/></item><item><title><![CDATA[Problems Plus 1: 15th Derivative of sin(x^3) at x = 0]]></title><description><![CDATA[In this video I go over Problem 1 which asks us to determine the 15th derivative at x = 0 for the function sin(x^3). Instead of manually solving the derivatives one by one, we can instead use the Maclaurin]]></description><link>http://direct.ecency.com/hive-128780/@mes/wpwwbvmx</link><guid isPermaLink="true">http://direct.ecency.com/hive-128780/@mes/wpwwbvmx</guid><category><![CDATA[hive-128780]]></category><dc:creator><![CDATA[mes]]></dc:creator><pubDate>Tue, 29 Aug 2023 04:52:03 GMT</pubDate><enclosure url="https://images.ecency.com/p/99pyU5Ga1kwr5bsMXthzYLbcngN4W2P8NtU9TWTdHC3HaQbjuuRfHesJoW1nsozNMUjzbjVo3QscCXUWBeJjyJeM53cAytbzmpkSxbpnDDpD7n5cKpXKDuTjMS7Wskfeyk?format=match&amp;mode=fit" length="0" type="false"/></item><item><title><![CDATA[Inverse Functions Part 2: One to One Functions and the Horizontal Line Test]]></title><description><![CDATA[In this video I clarify the inverse functions in which I defined in my earlier video to state that it is only applicable to one to one functions. This requirement is illustrated in trigonometric functions]]></description><link>http://direct.ecency.com/hive-128780/@mes/inverse-functions-part-2-one-to-one-functions-and-horizontal-line-test</link><guid isPermaLink="true">http://direct.ecency.com/hive-128780/@mes/inverse-functions-part-2-one-to-one-functions-and-horizontal-line-test</guid><category><![CDATA[hive-128780]]></category><dc:creator><![CDATA[mes]]></dc:creator><pubDate>Tue, 13 Jun 2023 17:12:00 GMT</pubDate><enclosure url="https://images.ecency.com/p/S5Eokt4BcQdk7EHeT1aYjzebg2hC7hkthT45eJMTXVqoKhQXTSrVd95mxnxCDWwSsFpNY1L?format=match&amp;mode=fit" length="0" type="false"/></item><item><title><![CDATA[Inverse Trigonometric Functions: Inverse Cosine, Sine, and Tan Functions]]></title><description><![CDATA[This video demonstrates how to get the inverse functions for the most common trigonometric functions in cosine, sine, and tan functions. Trigonometric functions are not one to one functions so the procedure]]></description><link>http://direct.ecency.com/hive-128780/@mes/inverse-trigonometric-functions-inverse-cosine-sine-tan</link><guid isPermaLink="true">http://direct.ecency.com/hive-128780/@mes/inverse-trigonometric-functions-inverse-cosine-sine-tan</guid><category><![CDATA[hive-128780]]></category><dc:creator><![CDATA[mes]]></dc:creator><pubDate>Mon, 12 Jun 2023 18:21:18 GMT</pubDate><enclosure url="https://images.ecency.com/p/S5Eokt4BcQdk7EHeT1aYjzebg2hC7hkthT45e5WPWRp1R75ybd9eU2zQ1RkySpQBneXwV4S?format=match&amp;mode=fit" length="0" type="false"/></item><item><title><![CDATA[Trigonometry: Proof of Law of Cosines (and Pythagorean Theorem)]]></title><description><![CDATA[In this video I show a simple geometric proof of the cosine law. This is very useful in real world applications. Also from the proof of the cosine law you can easily proof the Pythagorean theorem as well]]></description><link>http://direct.ecency.com/hive-128780/@mes/trigonometry-proof-of-law-of-cosines-and-pythagorean-theorem</link><guid isPermaLink="true">http://direct.ecency.com/hive-128780/@mes/trigonometry-proof-of-law-of-cosines-and-pythagorean-theorem</guid><category><![CDATA[hive-128780]]></category><dc:creator><![CDATA[mes]]></dc:creator><pubDate>Tue, 16 May 2023 16:38:30 GMT</pubDate><enclosure url="https://images.ecency.com/p/S5Eokt4BcQdk7EHeT1aYjzebg2hC7hkthT45ePypbGgocy1kUM28xZ3DPBwDjknFZfFeh2e?format=match&amp;mode=fit" length="0" type="false"/></item><item><title><![CDATA[Trigonometry Identities: sin(-x) = - sin(x) and cos(-x) = cos(x)]]></title><description><![CDATA[In this video I prove the two identities, sin(-x) = - sin(x) and cos(-x) = cos(x), which show that cosine is an even function while sine is an odd function. Download video notes: Watch video on: 3Speak:]]></description><link>http://direct.ecency.com/hive-128780/@mes/trigonometry-identities-sine-cosine-even-odd-functions</link><guid isPermaLink="true">http://direct.ecency.com/hive-128780/@mes/trigonometry-identities-sine-cosine-even-odd-functions</guid><category><![CDATA[hive-128780]]></category><dc:creator><![CDATA[mes]]></dc:creator><pubDate>Sat, 13 May 2023 17:36:54 GMT</pubDate><enclosure url="https://images.ecency.com/p/S5Eokt4BcQdk7EHeT1aYjzebg2hC7hkthT45eNkoL23uaM2G3Tvaop7W2HtomJpse9g2D4r?format=match&amp;mode=fit" length="0" type="false"/></item></channel></rss>