Constant function: Difference between revisions

Content deleted Content added
Basic properties: change to all 4, corresponding to the image, add math template, and some other copyedits
Line 7:
== Basic properties ==
[[Image:wiki constant function 175 200.png|270px|right|Constant function ''y''(''x'') = 4|thumb|An example of a constant function is {{math|1=''y''(''x'') = 4}}, because the value of {{math|''y''(''x'')}} is 4 regardless of the input value {{mvar|x}}.]]
As a real-valued function of a real-valued argument, a constant function has the general form {{math|1=''y''(''x'') = ''c''}} or just {{nowrap|{{math|1=''y'' = ''c''}}.}} For example, the function {{math|1=''y''(''x'') = 4}} is the specific constant function where the output value is {{math|1=''c'' = 4}}. The [[___domain of a function|___domain of this function]] is the set of all [[real number]]s. The [[Image (mathematics)|image]] of this function is the [[Singleton (mathematics)|singleton]] set {{math|{{mset|4}}}}. The independent variable {{nowrap|1=''x''}} does not appear on the right side of the function expression and so its value is "vacuously substituted"; namely {{math|1=''y''(0) = 24}}, {{math|1=''y''(−2.7) = 24}}, {{math|1=''y''(π) = 24}}, and so on. No matter what value of {{math|''x''}} is input, the output is {{math|4}}.<ref>{{cite book
| last = Tanton | first = James
| year = 2005