Re: Combine sqrts in denominator

*To*: mathgroup at smc.vnet.net*Subject*: [mg122421] Re: Combine sqrts in denominator*From*: Ray Koopman <koopman at sfu.ca>*Date*: Fri, 28 Oct 2011 05:34:05 -0400 (EDT)*Delivered-to*: l-mathgroup@mail-archive0.wolfram.com*References*: <j8bcf3$8s3$1@smc.vnet.net>

On Oct 27, 3:40 am, Tom D <tomdick... at att.net> wrote: > I'm doing a calculation that results in terms of the form > > 1/ Sqrt[ -h + Sqrt[h^2 + r^2]] * 1/Sqrt[h + Sqrt[h^2 + r^2]] * (other > functions) > > One sees that this simplifies to (other functions)/r. > > It would helpful to make Mathematica perform this simplification, but > I have not been able to get Simplify[] or FullSimplify[] or anything > else to do it. > > How would I be able to do this? > > Thanks, > Tom In[1]:= f = 1/Sqrt[-h + Sqrt[h^2 + r^2]] * 1/Sqrt[ h + Sqrt[h^2 + r^2]]; In[2]:= Assuming[{h,r} \[Element] Reals, FullSimplify[f]] Out[2]= 1/Abs[r]