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Re: Sqrt Problems

• To: mathgroup@smc.vnet.net
• Subject: [mg12162] Re: [mg12042] Sqrt Problems
• From: Bob Hanlon <BobHanlon@aol.com>
• Date: Mon, 27 Apr 1998 01:46:46 -0400

In a message dated 4/24/98 2:48:07 AM, REISER@HRTS.NRL.NAVY.MIL wrote:

>Forgive me if this is a simple question, but I am trying to get  "1" out
>of the following expression and I can't seem to figure out how:
>
>	u = Sqrt[a+I*b/a] * Sqrt[a^2+I*b] / Sqrt[a]
>
>Is there a package I'm missing or something?

It is not equal to one; however, I suspect that you are trying to do
something like

subst = Sqrt[x_]*Sqrt[y_] -> Sqrt[x*y]; 

u = Sqrt[a + I*b/a]*Sqrt[a^2 + I*b]/Sqrt[a] /. subst

Sqrt[(a^2 + I*b)*(a + (I*b)/a)]/Sqrt[a]

Simplify[%]

Sqrt[(a^2 + I*b)^2/a]/Sqrt[a]

PowerExpand[%]

(a^2 + I*b)/a

Simplify[%]

a + (I*b)/a

Bob Hanlon