History behind the choice of letters $h$ and $k$ for the vertex of a parabola?











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After failing to find a historical explanation for usage of letters $h$ and $k$ for the vertex of a parabola in most relatively recent textbooks in anglosphere, I turn to math.SE.



Is there any historical explanation for usage of these particular letters and if there is, what is it?










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  • Who exactly uses h and k for the said vertex?
    – Mikhail Katz
    Jan 23 '14 at 13:21










  • More or less all textbooks.
    – 2305843008139952128
    Jan 24 '14 at 12:04










  • As they say on Wikipedia: The perspective in this question may not represent a worldwide view of the subject. (I looked in a Scandinavian text book and found the vertex to be named $(m,n)$.)
    – Per Manne
    Jan 24 '14 at 15:08












  • Question edited to reflect these finds.
    – 2305843008139952128
    Jan 25 '14 at 5:53






  • 1




    It's not so much that these things are used as the vertex of a parabola. They are used as generic horizontal and vertical shifts. Yes, with parabolas: $y=x^2to y=(x-h)^2+k$, shifting the vertex $(0,0)$ to $(h,k)$, but also in other places, like $x^2+y^2=1to(x-h)^2+(y-k)^2=1$, shifting a circle's center in the same way. I still don't know why these two particular letters though.
    – alex.jordan
    Jan 25 '14 at 7:18

















up vote
4
down vote

favorite












After failing to find a historical explanation for usage of letters $h$ and $k$ for the vertex of a parabola in most relatively recent textbooks in anglosphere, I turn to math.SE.



Is there any historical explanation for usage of these particular letters and if there is, what is it?










share|cite|improve this question
























  • Who exactly uses h and k for the said vertex?
    – Mikhail Katz
    Jan 23 '14 at 13:21










  • More or less all textbooks.
    – 2305843008139952128
    Jan 24 '14 at 12:04










  • As they say on Wikipedia: The perspective in this question may not represent a worldwide view of the subject. (I looked in a Scandinavian text book and found the vertex to be named $(m,n)$.)
    – Per Manne
    Jan 24 '14 at 15:08












  • Question edited to reflect these finds.
    – 2305843008139952128
    Jan 25 '14 at 5:53






  • 1




    It's not so much that these things are used as the vertex of a parabola. They are used as generic horizontal and vertical shifts. Yes, with parabolas: $y=x^2to y=(x-h)^2+k$, shifting the vertex $(0,0)$ to $(h,k)$, but also in other places, like $x^2+y^2=1to(x-h)^2+(y-k)^2=1$, shifting a circle's center in the same way. I still don't know why these two particular letters though.
    – alex.jordan
    Jan 25 '14 at 7:18















up vote
4
down vote

favorite









up vote
4
down vote

favorite











After failing to find a historical explanation for usage of letters $h$ and $k$ for the vertex of a parabola in most relatively recent textbooks in anglosphere, I turn to math.SE.



Is there any historical explanation for usage of these particular letters and if there is, what is it?










share|cite|improve this question















After failing to find a historical explanation for usage of letters $h$ and $k$ for the vertex of a parabola in most relatively recent textbooks in anglosphere, I turn to math.SE.



Is there any historical explanation for usage of these particular letters and if there is, what is it?







math-history conic-sections






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edited Mar 20 '14 at 21:56









wanderer

2,4021816




2,4021816










asked Jan 23 '14 at 8:12









2305843008139952128

5528




5528












  • Who exactly uses h and k for the said vertex?
    – Mikhail Katz
    Jan 23 '14 at 13:21










  • More or less all textbooks.
    – 2305843008139952128
    Jan 24 '14 at 12:04










  • As they say on Wikipedia: The perspective in this question may not represent a worldwide view of the subject. (I looked in a Scandinavian text book and found the vertex to be named $(m,n)$.)
    – Per Manne
    Jan 24 '14 at 15:08












  • Question edited to reflect these finds.
    – 2305843008139952128
    Jan 25 '14 at 5:53






  • 1




    It's not so much that these things are used as the vertex of a parabola. They are used as generic horizontal and vertical shifts. Yes, with parabolas: $y=x^2to y=(x-h)^2+k$, shifting the vertex $(0,0)$ to $(h,k)$, but also in other places, like $x^2+y^2=1to(x-h)^2+(y-k)^2=1$, shifting a circle's center in the same way. I still don't know why these two particular letters though.
    – alex.jordan
    Jan 25 '14 at 7:18




















  • Who exactly uses h and k for the said vertex?
    – Mikhail Katz
    Jan 23 '14 at 13:21










  • More or less all textbooks.
    – 2305843008139952128
    Jan 24 '14 at 12:04










  • As they say on Wikipedia: The perspective in this question may not represent a worldwide view of the subject. (I looked in a Scandinavian text book and found the vertex to be named $(m,n)$.)
    – Per Manne
    Jan 24 '14 at 15:08












  • Question edited to reflect these finds.
    – 2305843008139952128
    Jan 25 '14 at 5:53






  • 1




    It's not so much that these things are used as the vertex of a parabola. They are used as generic horizontal and vertical shifts. Yes, with parabolas: $y=x^2to y=(x-h)^2+k$, shifting the vertex $(0,0)$ to $(h,k)$, but also in other places, like $x^2+y^2=1to(x-h)^2+(y-k)^2=1$, shifting a circle's center in the same way. I still don't know why these two particular letters though.
    – alex.jordan
    Jan 25 '14 at 7:18


















Who exactly uses h and k for the said vertex?
– Mikhail Katz
Jan 23 '14 at 13:21




Who exactly uses h and k for the said vertex?
– Mikhail Katz
Jan 23 '14 at 13:21












More or less all textbooks.
– 2305843008139952128
Jan 24 '14 at 12:04




More or less all textbooks.
– 2305843008139952128
Jan 24 '14 at 12:04












As they say on Wikipedia: The perspective in this question may not represent a worldwide view of the subject. (I looked in a Scandinavian text book and found the vertex to be named $(m,n)$.)
– Per Manne
Jan 24 '14 at 15:08






As they say on Wikipedia: The perspective in this question may not represent a worldwide view of the subject. (I looked in a Scandinavian text book and found the vertex to be named $(m,n)$.)
– Per Manne
Jan 24 '14 at 15:08














Question edited to reflect these finds.
– 2305843008139952128
Jan 25 '14 at 5:53




Question edited to reflect these finds.
– 2305843008139952128
Jan 25 '14 at 5:53




1




1




It's not so much that these things are used as the vertex of a parabola. They are used as generic horizontal and vertical shifts. Yes, with parabolas: $y=x^2to y=(x-h)^2+k$, shifting the vertex $(0,0)$ to $(h,k)$, but also in other places, like $x^2+y^2=1to(x-h)^2+(y-k)^2=1$, shifting a circle's center in the same way. I still don't know why these two particular letters though.
– alex.jordan
Jan 25 '14 at 7:18






It's not so much that these things are used as the vertex of a parabola. They are used as generic horizontal and vertical shifts. Yes, with parabolas: $y=x^2to y=(x-h)^2+k$, shifting the vertex $(0,0)$ to $(h,k)$, but also in other places, like $x^2+y^2=1to(x-h)^2+(y-k)^2=1$, shifting a circle's center in the same way. I still don't know why these two particular letters though.
– alex.jordan
Jan 25 '14 at 7:18












2 Answers
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http://www.latin-dictionary.net/search/latin/kardo7



Making a speculation, one could presume that "k" could refer to Latin "kardo", which when roughly translated, can mean "axis", but more specifically "hinge", which brings us to "h", which is the axis of symmetry.



When looking at the vertex form equation,



if "h" were to stand for "hinge", it would point out the fact that hinges can only pivot horizontally from their base part. With this said, I suppose that "h" shows us how much the line of the graph shifts horizontally on a coordinate plane from the origin.



Looking at "k" again,"k" shows the same thing as "h", but this time vertically.
A synonym that carries the same definition as "kardo" is Latin "tenon". This word directly translates into English "tendon". Tendons help organs shift vertically.






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  • You did a really nice job answering this question; I'd encourage you to expand by answering newer questions :)
    – Tianlalu
    Nov 20 at 4:10


















up vote
-1
down vote













According to http://mathforum.org/library/drmath/view/57023.html



"f" and "g" are used to denote functions, "i" and "j" are used for the imaginary unit, "a" - "e" are used for a lot of various different things. "h" and "k" were just not used for much else. Thus, someone decided that they would be good to use for vertices/centers.






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    2 Answers
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    2 Answers
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    http://www.latin-dictionary.net/search/latin/kardo7



    Making a speculation, one could presume that "k" could refer to Latin "kardo", which when roughly translated, can mean "axis", but more specifically "hinge", which brings us to "h", which is the axis of symmetry.



    When looking at the vertex form equation,



    if "h" were to stand for "hinge", it would point out the fact that hinges can only pivot horizontally from their base part. With this said, I suppose that "h" shows us how much the line of the graph shifts horizontally on a coordinate plane from the origin.



    Looking at "k" again,"k" shows the same thing as "h", but this time vertically.
    A synonym that carries the same definition as "kardo" is Latin "tenon". This word directly translates into English "tendon". Tendons help organs shift vertically.






    share|cite|improve this answer





















    • You did a really nice job answering this question; I'd encourage you to expand by answering newer questions :)
      – Tianlalu
      Nov 20 at 4:10















    up vote
    0
    down vote













    http://www.latin-dictionary.net/search/latin/kardo7



    Making a speculation, one could presume that "k" could refer to Latin "kardo", which when roughly translated, can mean "axis", but more specifically "hinge", which brings us to "h", which is the axis of symmetry.



    When looking at the vertex form equation,



    if "h" were to stand for "hinge", it would point out the fact that hinges can only pivot horizontally from their base part. With this said, I suppose that "h" shows us how much the line of the graph shifts horizontally on a coordinate plane from the origin.



    Looking at "k" again,"k" shows the same thing as "h", but this time vertically.
    A synonym that carries the same definition as "kardo" is Latin "tenon". This word directly translates into English "tendon". Tendons help organs shift vertically.






    share|cite|improve this answer





















    • You did a really nice job answering this question; I'd encourage you to expand by answering newer questions :)
      – Tianlalu
      Nov 20 at 4:10













    up vote
    0
    down vote










    up vote
    0
    down vote









    http://www.latin-dictionary.net/search/latin/kardo7



    Making a speculation, one could presume that "k" could refer to Latin "kardo", which when roughly translated, can mean "axis", but more specifically "hinge", which brings us to "h", which is the axis of symmetry.



    When looking at the vertex form equation,



    if "h" were to stand for "hinge", it would point out the fact that hinges can only pivot horizontally from their base part. With this said, I suppose that "h" shows us how much the line of the graph shifts horizontally on a coordinate plane from the origin.



    Looking at "k" again,"k" shows the same thing as "h", but this time vertically.
    A synonym that carries the same definition as "kardo" is Latin "tenon". This word directly translates into English "tendon". Tendons help organs shift vertically.






    share|cite|improve this answer












    http://www.latin-dictionary.net/search/latin/kardo7



    Making a speculation, one could presume that "k" could refer to Latin "kardo", which when roughly translated, can mean "axis", but more specifically "hinge", which brings us to "h", which is the axis of symmetry.



    When looking at the vertex form equation,



    if "h" were to stand for "hinge", it would point out the fact that hinges can only pivot horizontally from their base part. With this said, I suppose that "h" shows us how much the line of the graph shifts horizontally on a coordinate plane from the origin.



    Looking at "k" again,"k" shows the same thing as "h", but this time vertically.
    A synonym that carries the same definition as "kardo" is Latin "tenon". This word directly translates into English "tendon". Tendons help organs shift vertically.







    share|cite|improve this answer












    share|cite|improve this answer



    share|cite|improve this answer










    answered Nov 20 at 3:43









    Homo Videt

    11




    11












    • You did a really nice job answering this question; I'd encourage you to expand by answering newer questions :)
      – Tianlalu
      Nov 20 at 4:10


















    • You did a really nice job answering this question; I'd encourage you to expand by answering newer questions :)
      – Tianlalu
      Nov 20 at 4:10
















    You did a really nice job answering this question; I'd encourage you to expand by answering newer questions :)
    – Tianlalu
    Nov 20 at 4:10




    You did a really nice job answering this question; I'd encourage you to expand by answering newer questions :)
    – Tianlalu
    Nov 20 at 4:10










    up vote
    -1
    down vote













    According to http://mathforum.org/library/drmath/view/57023.html



    "f" and "g" are used to denote functions, "i" and "j" are used for the imaginary unit, "a" - "e" are used for a lot of various different things. "h" and "k" were just not used for much else. Thus, someone decided that they would be good to use for vertices/centers.






    share|cite|improve this answer

























      up vote
      -1
      down vote













      According to http://mathforum.org/library/drmath/view/57023.html



      "f" and "g" are used to denote functions, "i" and "j" are used for the imaginary unit, "a" - "e" are used for a lot of various different things. "h" and "k" were just not used for much else. Thus, someone decided that they would be good to use for vertices/centers.






      share|cite|improve this answer























        up vote
        -1
        down vote










        up vote
        -1
        down vote









        According to http://mathforum.org/library/drmath/view/57023.html



        "f" and "g" are used to denote functions, "i" and "j" are used for the imaginary unit, "a" - "e" are used for a lot of various different things. "h" and "k" were just not used for much else. Thus, someone decided that they would be good to use for vertices/centers.






        share|cite|improve this answer












        According to http://mathforum.org/library/drmath/view/57023.html



        "f" and "g" are used to denote functions, "i" and "j" are used for the imaginary unit, "a" - "e" are used for a lot of various different things. "h" and "k" were just not used for much else. Thus, someone decided that they would be good to use for vertices/centers.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered Dec 22 '14 at 22:41









        dardeshna

        362213




        362213






























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