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Re: Working with Log

  • To: mathgroup at smc.vnet.net
  • Subject: [mg112141] Re: Working with Log
  • From: Themis Matsoukas <tmatsoukas at me.com>
  • Date: Thu, 2 Sep 2010 02:29:56 -0400 (EDT)

To summarize the responses, there are two solutions:

1: Tell mathematica that the arguments are positive numbers:

FullSimplify[2 Log[a] + 3 Log[b], Assumptions -> {a > 0, b > 0, c > 0}]

Log[a^2 b^3]

2: Use a replacement rule

2 Log[a] + 3 Log[b] //. a_ Log[b_] + c_ Log[d_] -> Log[b^a d^c]

Log[a^2 b^3]

Thanks to all.

Themis


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