Re: Simplifying Sqrt[a^2*d^2] -> a*d
- To: mathgroup at smc.vnet.net
- Subject: [mg8395] Re: Simplifying Sqrt[a^2*d^2] -> a*d
- From: vvs124 at rsphy1.anu.edu.au (Victoria Steblina)
- Date: Tue, 26 Aug 1997 20:41:35 -0400
- Organization: Australian National University
- Sender: owner-wri-mathgroup at wolfram.com
In article <5tjftc$drn at smc.vnet.net>
carlos at mars.Colorado.EDU (Carlos A. Felippa) writes:
> I want Sqrt[a^2*d^2] to be automatically simplified to a*d
> wherever it appears in a very complex expression.
>
> In another system I simply declare a and d real nonnegative and let the
> program figure out the rest. How do I do that in Mathematica?
> The obvious rule expr/.{Sqrt[a^2*d^2]->a*d} does not work.
>
>
You can do it this way:
(local) In[1]:= Unprotect[Sqrt];
Sqrt[a^2*d^2] = a*d;
Protect[Sqrt];
(local) In[4]:= Sqrt[a^2*d^2] + Sqrt[a^2*d^2]^3
3 3
(local) Out[4]= a d + a d
Cheers,
Victoria