D[UnitStep[x], x] == Piecewise[{{Indeterminate, x == 0}}, 0]

Cell[BoxData[RowBox[List[RowBox[List["D", "[", RowBox[List[RowBox[List["UnitStep", "[", "x", "]"]], ",", "x"]], "]"]], "\[Equal]", RowBox[List["Piecewise", "[", RowBox[List[RowBox[List["{", RowBox[List["{", RowBox[List["Indeterminate", ",", RowBox[List["x", "\[Equal]", "0"]]]], "}"]], "}"]], ",", "0"]], "]"]]]]]]

<math xmlns='http://www.w3.org/1998/Math/MathML' mathematica:form='TraditionalForm' xmlns:mathematica='http://www.wolfram.com/XML/'> <semantics> <mrow> <mfrac> <mrow> <mo> &#8706; </mo> <mrow> <semantics> <mi> &#952; </mi> <annotation-xml encoding='MathML-Content'> <ci> UnitStep </ci> </annotation-xml> </semantics> <mo> ( </mo> <mi> x </mi> <mo> ) </mo> </mrow> </mrow> <mrow> <mo> &#8706; </mo> <mi> x </mi> </mrow> </mfrac> <mo> &#63449; </mo> <mrow> <mo> &#62305; </mo> <mtable> <mtr> <mtd> <mi> &#191; </mi> </mtd> <mtd> <mrow> <mi> x </mi> <mo> &#63449; </mo> <mn> 0 </mn> </mrow> </mtd> </mtr> </mtable> </mrow> </mrow> <annotation-xml encoding='MathML-Content'> <apply> <eq /> <apply> <partialdiff /> <bvar> <ci> x </ci> </bvar> <apply> <ci> UnitStep </ci> <ci> x </ci> </apply> </apply> <apply> <ci> Piecewise </ci> <list> <list> <ci> &#191; </ci> <apply> <eq /> <ci> x </ci> <cn type='integer'> 0 </cn> </apply> </list> </list> </apply> </apply> </annotation-xml> </semantics> </math>

Cell[BoxData[RowBox[List[RowBox[List["HoldPattern", "[", RowBox[List[SubscriptBox["\[PartialD]", RowBox[List["x_"]]], RowBox[List["UnitStep", "[", "x_", "]"]]]], "]"]], "\[RuleDelayed]", RowBox[List["\[Piecewise]", GridBox[List[List["Indeterminate", RowBox[List["x", "\[Equal]", "0"]]]], Rule[ColumnAlignments, List[Left]], Rule[ColumnSpacings, 1.2`], Rule[ColumnWidths, Automatic]]]]]]]]

2007-05-02