Re: "Nice" complex form

*To*: mathgroup at smc.vnet.net*Subject*: [mg131597] Re: "Nice" complex form*From*: Bob Hanlon <hanlonr357 at gmail.com>*Date*: Tue, 10 Sep 2013 03:34:07 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*Delivered-to*: l-mathgroup@wolfram.com*Delivered-to*: mathgroup-outx@smc.vnet.net*Delivered-to*: mathgroup-newsendx@smc.vnet.net*References*: <20130909040609.9789D6A14@smc.vnet.net>

The form that you are seeking is not "simpler" so you would need to force it. (expr1 = Sqrt[a - 4]) // LeafCount 7 expr2 = expr1 /. Sqrt[x_] -> I Sqrt[-x] I*Sqrt[4 - a] expr2 // LeafCount 13 Simplify[expr1 == expr2, a - 4 < 0] True Bob Hanlon On Mon, Sep 9, 2013 at 12:06 AM, <sam.takoy at yahoo.com> wrote: > Hi, > > Can I get > > Assuming[a - 4 < 0, Sqrt[a - 4]] > > to "simplify" to > > I Sqrt[4 - a] > > ? > > Thanks, > > Sam > > >

**References**:**"Nice" complex form***From:*sam.takoy@yahoo.com