arctan with Windows calculator

[ronv...@gmail.com]

My RPN calculator does not have trig functions so I am trying to use
the Windows calculator and I am having trouble with simple data entry.
I am trying to convert rectangular to polar coordinates but I keep
getting the wrong answers. I have no problem finding r but with theta
I need to find the arctangent of y/x or (tan^-1(y/x)) and I am not
getting the right answer. I don't know how I can get confused by such
a simple thing. Can someone explain how to enter tan^-1 on the Windows
calculator?

Thanks,
Ron

[mensa...@aol.com]

Check the Inverse box [x]Inv before clicking on the [Tan} button.

>
> Thanks,
> Ron

[Greg Neill]

<ronv...@gmail.com> wrote in message
news:1181177677.0...@q66g2000hsg.googlegroups.com...

Check whether the result setting is for degrees or radians.

[ronv...@gmail.com]

On Jun 6, 8:07 pm, "mensana...@aol.compost" <mensana...@aol.com>
wrote:

> Check the Inverse box [x]Inv before clicking on the [Tan} button.
>

Thanks! That worked.
I'm not even going to tell you how I was trying to get it to work. I'm
such an idiot.

[Passerby]

After doing what others have posted, if you want an improved (and
free) calculator for XP from Microsoft, you might want to install the
PowerToys Power Calculator. Ref:
<http://www.microsoft.com/windowsxp/downloads/powertoys/xppowertoys.mspx>

[Zdislav V. Kovarik]

Caution: If you use arctan(y/x) for your angle, you will get wrong
answers in 50% of the cases. Which ones? The ones with x<0. Just look at
the sketch, or at the fact that y/x = (-y)/(-x).

A better approach is: 2*arctan(y/(x+r)).

It fails only when x<=0 and y=0 (division by zero), but that can be
handled separately.

To get arctangent: use View:Scientific
enter your ratio, then
click Inv - tan

voila!

Cheers, ZVK(Slavek).

[xti...@gmail.com]

Holy shit, the calculator is the best thing about Windows.