Talk:Extraneous and missing solutions: Difference between revisions

Revision as of 20:31, 31 January 2008

Revision as of 23:24, 1 March 2008

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I expanded on this idea a bit, starting with some very simple examples, including discussion of operations that remove solutions, and outlining a more general and (hopefully) more understandable categorization of what operations do what to the solution set. Feel free to revise. [[User:Dcoetzee|Dcoetzee]] 20:31, 31 January 2008 (UTC)

== Possible errors ==

I see a couple of things in this article that don't seem right. Firstly, with the example <math>\sqrt{x}=-1</math>, the article says x=1 is not a solution. That means <math>\surd</math> is being used to mean positive square root (as is common), but in that case the equation has no solutions by definition, so is a rather poor example. Secondly, at the end it says multiplication is surjective by not injective. It's quite clearly not surjective since it's image is just {0}. Am I missing something here, or should I just fix it? --[[User:Tango|Tango]] ([[User talk:Tango|talk]]) 23:24, 1 March 2008 (UTC)