MathGroup Archive 2006

[Date Index] [Thread Index] [Author Index]

Search the Archive

Re: simplify a trig expression


Murray Eisenberg schrieb:
> A direct substitution (with paper and pencil) gives that the integral of 
>   Cos[x]/(Sin[x] + 1) is Log[Sin[x] + 1].  This is valid provided Sin[x] 
> is not -1.
> 
> Mathematica gives:
> 
>    Integrate[Cos[x]/(Sin[x] + 1), x]
> 2 Log[Cos[x/2] + Sin[x/2]]
> 
> Is there some simple way to coerce the latter Mathematica-supplied 
> result into the paper-and-pencil answer?

In[]
Integrate[Cos[x]/(Sin[x] + 1), x] //
Times[#, 1/2] & //
Map[Power[#, 2] &, #] & //
FullSimplify

Out[]
Log[1 + Sin[x]]


-- 

Roland Franzius


  • Prev by Date: Re: simplify a trig expression
  • Next by Date: Re: simultaneous nonlinear regression of a lot of data
  • Previous by thread: Re: simplify a trig expression
  • Next by thread: Re: simplify a trig expression