Re: how to get the angle from the cosine, etc.

From: Sean Hunt (seanstewarthunt_at_hotmail.com)
Date: 10/03/04 

Date: 3 Oct 2004 00:31:34 -0700

Adam,

  Thank you very much for the response!

  I'm actually looking for a way to get the angle (in radians), given
that you already have the sine and cosine of the angle. I'm trying to
derive an equation to go back and forth rather than a look-up process,
so that the angle can be calculated as a result, and not approximated
by finding a table value that comes close.

  On the surface it looks like a fairly easy correlation, but I
haven't been able to calculate the angle given sine and cosine. Now
I'm beginning to think that this might be a calculus problem rather
than a trigenometry problem.

Thanx...
   Sean

"Adam" <addam@rogers.com> wrote in message news:<sJydnV1_N5ezycLcRVn-uw@rogers.com>...
> "Sean Hunt" <seanstewarthunt@hotmail.com> wrote in message
> news:22c674bb.0410021705.72383428@posting.google.com...
> > Folks,
> >
> > If you already have the cosine, how do you get the angle itself?
> >
> > I just can't seem to create the equation to go from cosine to angle
> > or vice-versa. It's really been bothering me recently, as I believe
> > it isn't a complicated derivation, just one that isn't occuring to me!
> > Many thanks in advance.
> >
> > Thanx...
> > Sean
>
> Hi there,
>
> I'm in physics and, even so, the following site really helped me grasp what
> trigonometry is all about. I really was just using it without thinking about
> it. That is, I knew the forumals and procedures, but not the meaning behind
> it all.
>
> Basically, the cosine function is just a table. You look at the angle and
> then find the value. To do the reverse, you find the value and look at the
> angle.
>
> Perhaps you are thinking of the Taylor series expansion for cosine and
> wanting to find the angle?

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