Services & Resources / Wolfram Forums
-----
 /
MathGroup Archive
2006
*January
*February
*March
*April
*May
*June
*July
*August
*September
*October
*November
*December
*Archive Index
*Ask about this page
*Print this page
*Give us feedback
*Sign up for the Wolfram Insider

MathGroup Archive 2006

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

Search the Archive

Re: Trigonometric simplification

  • To: mathgroup at smc.vnet.net
  • Subject: [mg68881] Re: Trigonometric simplification
  • From: carlos at colorado.edu
  • Date: Tue, 22 Aug 2006 05:20:11 -0400 (EDT)
  • References: <ecbnnc$r29$1@smc.vnet.net><ecc2pn$ajl$1@smc.vnet.net>
  • Sender: owner-wri-mathgroup at wolfram.com

> Hi Carlos,
>
> Using TrigReduce before Simplify will do it:
>
> r = Tan[a]^2/(Sec[a]^2)^(3/2);
> Simplify[TrigReduce[r], Assumptions -> {a > 0, Sec[a] > 0}]
>
> --> Cos[a]*Sin[a]^2
>
> Best regards,
> Jean-Marc

Thanks, that works perfectly.  Actually Sec[a]>0 as assumption
is sufficient. This is correct from the problem source, since
the angle is in the range (-Pi/2,Pi/2)

Here is a related question.  How can I get Mathematica to pass from

   d = 2 + 3*Cos[a] + Cos[3*a]     (* leaf count 10 *)

to

    1 + 2*Cos[a]^3                  (* leaf count 8 *)

TrigExpand[d] gives

   2 + 3*Cos[a] + Cos[a]^3 - 3*Cos[a]*Sin[a]^2

Applying Simplify to that yields  2 + 3*Cos[a] + Cos[3*a]  so we are
back to the beggining.


  • Prev by Date: Re: Trigonometric simplification
  • Next by Date: Re: Trigonometric simplification
  • Previous by thread: Re: Trigonometric simplification
  • Next by thread: Re: Re: Trigonometric simplification