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Re: Output display of exponential function in Mathematica

  • To: mathgroup at smc.vnet.net
  • Subject: [mg62547] Re: Output display of exponential function in Mathematica
  • From: Peter Pein <petsie at dordos.net>
  • Date: Sun, 27 Nov 2005 02:41:41 -0500 (EST)
  • References: <dm958i$6p8$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

Bookreader schrieb:
> How can I get Mathematica to display 25(5^h) when I input 5^(2+h)?

This is not easy, because Mathematica simplifies the input 25*5^h 
automagically to 5^(2+h).
In[1]:= 5^(2 + h) /. a_^(b_?NumberQ + c_) :> a^b*HoldForm[a^c]
Out[1]= 25 5^h

> 
> Also, is there a way to solve this question?  I've read the help.  I'm
> studying for my final and am trying to find the answer to an
> even-numbered question from my text.
> 
> Factor 5^(7x/2) - 5^(x^2), with sqrt(5^x) being one of the factors.
> The answer I get is sqrt(5^x) times( (5^7)-1).
Who/what gave this answer? I'm sure you *don't* want Mathematica behave 
like this.
(PowerExpand[Expand[Sqrt[5^x]^7*(1 - Sqrt[5^x]^(2*x - 7))]]
  yields 5^((7*x)/2) - 5^x^2 for example).
> 
> Thanks for showing me how to do these.
> 


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