Re: How to get sqrt(Year^2)===Year?

*To*: mathgroup at smc.vnet.net*Subject*: [mg75761] Re: [mg75724] How to get sqrt(Year^2)===Year?*From*: Sseziwa Mukasa <mukasa at jeol.com>*Date*: Thu, 10 May 2007 05:08:44 -0400 (EDT)*References*: <200705090833.EAA14797@smc.vnet.net>

On May 9, 2007, at 4:33 AM, Hatto von Aquitanien wrote: > If I have some expression which takes the square root of a square, it > evaluates leaving the whole square root expression unchanged. > > Year == (Year^2)^(1/2) > > just returns what I entered when evaluated. > > Year == Year > > evaluates to True. > > How do I persuade Mathematica to evaluate the first expression > completely? It is evaluating it completely, Year == (Year^2)^(1/2) is True only when Year is non-negative, so you have to tell Mathematica that that's the case: Simplify[Year==(Year^2)^(1/2),Year>=0] Regards, Ssezi

**References**:**How to get sqrt(Year^2)===Year?***From:*Hatto von Aquitanien <abbot@AugiaDives.hre>