Re: TraditionForm Appears to be Inconsistent

*To*: mathgroup at smc.vnet.net*Subject*: [mg99576] Re: [mg99551] TraditionForm Appears to be Inconsistent*From*: Murray Eisenberg <murray at math.umass.edu>*Date*: Fri, 8 May 2009 00:16:53 -0400 (EDT)*Organization*: Mathematics & Statistics, Univ. of Mass./Amherst*References*: <200905071040.GAA19666@smc.vnet.net>*Reply-to*: murray at math.umass.edu

Because, I presume, Mathematica knows that Cos[x] always has the same value as Sin[x + \[Pi]/2] no matter what x is; it evaluates both sides of that equation and then decrees the equation True. But Mathematica seems cautious if, for example, you enter Cos[a + b I] + Sin[a + b I] which it leaves unevaluated further. Then if you enter, say, Exp[I \[Theta]]==Cos[\[Theta]]+I Sin[\[Theta]]/.\[Theta]->a+b I then it returns the result without further evaluation. uk.org.microserf at googlemail.com wrote: > Hi > > The Mathematica 7 documentation says that > > TraditionalForm[Exp[I \[Theta]] == Cos[\[Theta]] + I Sin[\[Theta]]] > > will display the expression in traditional form, and indeed it does. > However, the following evaluates the expression and then displays True > in traditional form: > > TraditionalForm[Cos[x] == Sin[x + \[Pi]/2]] > > Why is TraditionalForm behaving differently in these two apparently > identical situations, and how can I get Mathematica to display this > trigonometric identity in traditional form? > > Thanks in advance > > Chris > -- Murray Eisenberg murray at math.umass.edu Mathematics & Statistics Dept. Lederle Graduate Research Tower phone 413 549-1020 (H) University of Massachusetts 413 545-2859 (W) 710 North Pleasant Street fax 413 545-1801 Amherst, MA 01003-9305

**References**:**TraditionForm Appears to be Inconsistent***From:*uk.org.microserf@googlemail.com