User talk:79.74.224.212

Your recent editing history at Rationalisation (mathematics) shows that you are currently engaged in an edit war; that means that you are repeatedly changing content back to how you think it should be, when you have seen that other editors disagree. To resolve the content dispute, please do not revert or change the edits of others when you are reverted. Instead of reverting, please use the talk page to work toward making a version that represents consensus among editors. The best practice at this stage is to discuss, not edit-war. See the bold, revert, discuss cycle for how this is done. If discussions reach an impasse, you can then post a request for help at a relevant noticeboard or seek dispute resolution. In some cases, you may wish to request temporary page protection.

Being involved in an edit war can result in you being blocked from editing&mdash;especially if you violate the three-revert rule, which states that an editor must not perform more than three reverts on a single page within a 24-hour period. Undoing another editor's work—whether in whole or in part, whether involving the same or different material each time—counts as a revert. Also keep in mind that while violating the three-revert rule often leads to a block, you can still be blocked for edit warring&mdash;even if you do not violate the three-revert rule&mdash;should your behavior indicate that you intend to continue reverting repeatedly. D.Lazard (talk) 10:18, 28 November 2020 (UTC)

December 2020
Welcome to Wikipedia. Although everyone is welcome to contribute constructively to the encyclopedia, your addition of one or more external links to the page Rationalisation (mathematics) has been reverted. Your edit here to Rationalisation (mathematics) was reverted by an automated bot that attempts to remove links which are discouraged per our external links guideline. The external link(s) you added or changed (https://www.youtube.com/watch?v=08l_XaG1DuI&ab_channel=JonAnderson) is/are on my list of links to remove and probably shouldn't be included in Wikipedia. If the external link you inserted or changed was to a media file (e.g. music or video) on an external server, then note that linking to such files may be subject to Wikipedia's copyright policy, as well as other parts of our external links guideline. If the information you linked to is indeed in violation of copyright, then such information should not be linked to. Please consider using our upload facility to upload a suitable media file, or consider linking to the original. If you were trying to insert an external link that does comply with our policies and guidelines, then please accept my creator's apologies and feel free to undo the bot's revert. However, if the link does not comply with our policies and guidelines, but your edit included other, constructive, changes to the article, feel free to make those changes again without re-adding the link. Please read Wikipedia's external links guideline for more information, and consult my list of frequently-reverted sites. For more information about me, see my FAQ page. Thanks! --XLinkBot (talk) 09:47, 6 December 2020 (UTC) If this is a shared IP address, and you didn't make the edit, please ignore this notice.

Hello, I'm XLinkBot. I wanted to let you know that one or more external links you added to Rationalisation (mathematics) have been removed because they seemed to be inappropriate for an encyclopedia. If you think I made a mistake, or if you have any questions, you can leave me a message on my talk page, or take a look at our guidelines about links. Your edit here to Rationalisation (mathematics) was reverted by an automated bot that attempts to remove links which are discouraged per our external links guideline. The external link(s) you added or changed (https://www.youtube.com/watch?v=08l_XaG1DuI&ab_channel=JonAnderson) is/are on my list of links to remove and probably shouldn't be included in Wikipedia. If the external link you inserted or changed was to a media file (e.g. music or video) on an external server, then note that linking to such files may be subject to Wikipedia's copyright policy, as well as other parts of our external links guideline. If the information you linked to is indeed in violation of copyright, then such information should not be linked to. Please consider using our upload facility to upload a suitable media file, or consider linking to the original. If you were trying to insert an external link that does comply with our policies and guidelines, then please accept my creator's apologies and feel free to undo the bot's revert. However, if the link does not comply with our policies and guidelines, but your edit included other, constructive, changes to the article, feel free to make those changes again without re-adding the link. Please read Wikipedia's external links guideline for more information, and consult my list of frequently-reverted sites. For more information about me, see my FAQ page. Thanks! --XLinkBot (talk) 18:37, 7 December 2020 (UTC) If this is a shared IP address, and you didn't make the edit, please ignore this notice.

Absolute values
The following things are all true: It is the last of the three facts that is relevant, and absolute value bars are inappropriate there. --JBL (talk) 20:12, 7 December 2020 (UTC)
 * For a nonnegative real number a, we have $$\sqrt{a^2} = a$$
 * For any real number a, we have $$\sqrt{a^2} = |a|$$
 * The expression $$ (\sqrt{a})^2$$ is defined as a real quantity for nonnegative a only, and it is equal to a