MathGroup Archive: August 2011 [00416]

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

Simplifying certain trigonometric expressions

To: mathgroup at smc.vnet.net
Subject: [mg121034] Simplifying certain trigonometric expressions
From: SamTakoy <pavelgrinfeld at gmail.com>
Date: Wed, 24 Aug 2011 03:14:44 -0400 (EDT)
Delivered-to: l-mathgroup@mail-archive0.wolfram.com

Hi,

My Mathematica has no problem with

Assuming[x > 0 && y > 0, Cos[ArcTan[y/x]] // FullSimplify]

yielding x/Sqrt[x^2 + y^2], but can't do anything with

Assuming[x > 0 && y > 0, Cos[2 ArcTan[y/x]] // FullSimplify].

How does one overcome this?

Thanks,

Pavel

Follow-Ups:
- Re: Simplifying certain trigonometric expressions
  - From: Heike Gramberg <heike.gramberg@gmail.com>

Prev by Date: Limits of FindIntegerNullVector[]?

Next by Date: Nested List Abs[]

Previous by thread: Limits of FindIntegerNullVector[]?

Next by thread: Re: Simplifying certain trigonometric expressions