Re: Trigonometry, sine theorem.
- To: mathgroup at smc.vnet.net
- Subject: [mg30746] Re: Trigonometry, sine theorem.
- From: "Allan Hayes" <hay at haystack.demon.co.uk>
- Date: Sun, 9 Sep 2001 03:26:40 -0400 (EDT)
- References: <9ncfvr$pu3$1@smc.vnet.net>
- Sender: owner-wri-mathgroup at wolfram.com
Matthias,
The sine rule does not give three independent equations.
I suggest using the cosine rule:
a^2 == b^2+c^2-2b c Cos[A]
This will also enable you to distinguish obtuse from acute angles.
--
Allan
---------------------
Allan Hayes
Mathematica Training and Consulting
Leicester UK
www.haystack.demon.co.uk
hay at haystack.demon.co.uk
Voice: +44 (0)116 271 4198
Fax: +44 (0)870 164 0565
<Matthias.Bode at oppenheim.de> wrote in message
news:9ncfvr$pu3$1 at smc.vnet.net...
> Dear Colleagues,
>
> I have a non-special triangle with sides
>
> a = 75mm, b = 67 mm, c = 117 mm.
>
> I just want to calculate the angles alpha, beta, gamma using a/b =
> sin[alpha]/sin[beta] &c. for a/c and b/c.
>
> All my attempts with FindRoot, Solve, including prior TrigToExp
> transformation were nugatory.
>
> How?
>
> Best regards,
>
> Matthias Bode
> Sal. Oppenheim jr. & Cie. KGaA
> Koenigsberger Strasse 29
> D-60487 Frankfurt am Main
> GERMANY
> Tel.: +49(0)69 71 34 53 80
> Mobile: +49(0)172 6 74 95 77
> Fax: +49(0)69 71 34 63 80
> E-mail: matthias.bode at oppenheim.de
> Internet: http://www.oppenheim.de
>
>