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From: "Imran " <imran.shafi@gmail.com>
Newsgroups: comp.soft-sys.matlab
Subject: Re: Equations depicting 2 DOF
Date: Mon, 12 Apr 2010 12:42:05 +0000 (UTC)
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Dear Rune
thanks for your reply
in fact i want to find the thetas! not their sin or cosine
regards,
Imran
Rune Allnor <allnor@tele.ntnu.no> wrote in message <9232e424-2373-46c9-95e4-b6c24ba9c71c@i25g2000yqm.googlegroups.com>...
> On 12 apr, 12:12, "Imran " <imran.sh...@gmail.com> wrote:
> > Dear All
> > Good day
> > I have to find solution to following two equations
> >
> > L1 Cos (theta1)+ L2 Cos (theta2)=x
> > L1 Sin (theta1) + L2 Sin (theta2)=y
> > here L1, L2, x and y are known
> >
> > is there any direct function available?
> 
> Depends on what you want to solve for. If you are happy to
> find the cosines and sines (as opposed to the angles) all
> you need to do is to add the constraints
> 
> cos(theta1)^2 + sin(theta1)^2 = 1
> cos(theta2)^2 + sin(theta2)^2 = 1
> 
> in which case you will end up with four equations in four
> unknowns, which are easily solved.
> 
> If you want to find the angles theta1 and theta2 you have
> trouble, as the inverse sines and cosine functions are ambiguous.
> 
> Rune