What's wrong with my arc tangens calculation?

Discussion in 'Python' started by xliiv, Sep 14, 2012.

  1. xliiv

    xliiv Guest

    I do some math with python:

    import math as m
    m.degrees(m.atan(2))
    >>> 63.43494882292201


    but when i lookup tg in a paper table (last decade math book) i've got these values:

    tg(63'10'') = 1.9768
    tg(63'20'') = 1.9912
    tg(63'30'') = 2.0057

    For me python should return something more like 63'2x'' than 63'4x''(becasue 63'30'' is higher than 2.0)

    what's wrong?
     
    xliiv, Sep 14, 2012
    #1
    1. Advertising

  2. On Fri, Sep 14, 2012 at 8:49 PM, xliiv <> wrote:
    > I do some math with python:
    >
    > import math as m
    > m.degrees(m.atan(2))
    >>>> 63.43494882292201

    >
    > but when i lookup tg in a paper table (last decade math book) i've got these values:
    >
    > tg(63'10'') = 1.9768
    > tg(63'20'') = 1.9912
    > tg(63'30'') = 2.0057
    >
    > For me python should return something more like 63'2x'' than 63'4x''(becasue 63'30'' is higher than 2.0)


    According to Google:
    ..43494882292201 degrees = 26.0969294 arcminutes

    So I would say that your table and Python are in agreement. Do you
    know what the notation 63'30" means?

    ChrisA
     
    Chris Angelico, Sep 14, 2012
    #2
    1. Advertising

  3. xliiv

    Laszlo Nagy Guest


    > but when i lookup tg in a paper table (last decade math book) i've got these values:
    >
    > tg(63'10'') = 1.9768
    > tg(63'20'') = 1.9912
    > tg(63'30'') = 2.0057
    >
    > For me python should return something more like 63'2x'' than 63'4x''(becasue 63'30'' is higher than 2.0)
    >
    > what's wrong?
    >

    63° 30" is 63.5°. So nothing is wrong. (You know, 1° = 60 arc second!)
     
    Laszlo Nagy, Sep 14, 2012
    #3
  4. xliiv

    xliiv Guest

    On Friday, September 14, 2012 12:55:06 PM UTC+2, Laszlo Nagy wrote:
    > > but when i lookup tg in a paper table (last decade math book) i've got these values:

    >
    > >

    >
    > > tg(63'10'') = 1.9768

    >
    > > tg(63'20'') = 1.9912

    >
    > > tg(63'30'') = 2.0057

    >
    > >

    >
    > > For me python should return something more like 63'2x'' than 63'4x''(becasue 63'30'' is higher than 2.0)

    >
    > >

    >
    > > what's wrong?

    >
    > >

    >
    > 63� 30" is 63.5�. So nothing is wrong. (You know, 1� = 60 arc second!)


    So the wrong part is me ;)
    The python's 63.43494882292201 is degrees (according to function math.degrees)
    but book's value is in minutes. Clearified Thanks, all.
     
    xliiv, Sep 14, 2012
    #4
  5. xliiv

    xliiv Guest

    On Friday, September 14, 2012 12:55:06 PM UTC+2, Laszlo Nagy wrote:
    > > but when i lookup tg in a paper table (last decade math book) i've got these values:

    >
    > >

    >
    > > tg(63'10'') = 1.9768

    >
    > > tg(63'20'') = 1.9912

    >
    > > tg(63'30'') = 2.0057

    >
    > >

    >
    > > For me python should return something more like 63'2x'' than 63'4x''(becasue 63'30'' is higher than 2.0)

    >
    > >

    >
    > > what's wrong?

    >
    > >

    >
    > 63� 30" is 63.5�. So nothing is wrong. (You know, 1� = 60 arc second!)


    So the wrong part is me ;)
    The python's 63.43494882292201 is degrees (according to function math.degrees)
    but book's value is in minutes. Clearified Thanks, all.
     
    xliiv, Sep 14, 2012
    #5
  6. On 14/09/2012 11:54, Chris Angelico wrote:
    > On Fri, Sep 14, 2012 at 8:49 PM, xliiv <> wrote:
    >> I do some math with python:
    >>
    >> import math as m
    >> m.degrees(m.atan(2))
    >>>>> 63.43494882292201

    >>
    >> but when i lookup tg in a paper table (last decade math book) i've got these values:
    >>
    >> tg(63'10'') = 1.9768
    >> tg(63'20'') = 1.9912
    >> tg(63'30'') = 2.0057
    >>
    >> For me python should return something more like 63'2x'' than 63'4x''(becasue 63'30'' is higher than 2.0)

    >
    > According to Google:
    > .43494882292201 degrees = 26.0969294 arcminutes
    >
    > So I would say that your table and Python are in agreement. Do you
    > know what the notation 63'30" means?
    >
    > ChrisA
    >


    Somebody or something has a length, height or width of 63 feet 30 inches? :)

    --
    Cheers.

    Mark Lawrence.
     
    Mark Lawrence, Sep 14, 2012
    #6
  7. On Fri, Sep 14, 2012 at 11:13 PM, Mark Lawrence <> wrote:
    > Somebody or something has a length, height or width of 63 feet 30 inches? :)


    Sounds like the height of a building with a barometer. The thirty
    inches, of course, being the height of the barometer.

    ChrisA
    (big, big barometer)
     
    Chris Angelico, Sep 14, 2012
    #7
    1. Advertising

Want to reply to this thread or ask your own question?

It takes just 2 minutes to sign up (and it's free!). Just click the sign up button to choose a username and then you can ask your own questions on the forum.
Similar Threads
  1. Replies:
    3
    Views:
    1,109
  2. pkirk25

    main(int arc, char *argv[])

    pkirk25, Nov 13, 2006, in forum: C++
    Replies:
    9
    Views:
    1,289
  3. Dexter
    Replies:
    0
    Views:
    369
    Dexter
    Mar 28, 2008
  4. Martin DeMello

    neat idea from arc

    Martin DeMello, Jan 29, 2008, in forum: Ruby
    Replies:
    9
    Views:
    118
    Pit Capitain
    Jan 31, 2008
  5. ARC Surveillance

    , Dec 6, 2005, in forum: Javascript
    Replies:
    0
    Views:
    94
Loading...

Share This Page