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I'm trying to calculate the euclidean distance between two points (x1,y1) and (x2,y2) which is

sqrt( (x2-x1)^2 + (y2-y1)^2 )

Is there a way to calculate this easily with Emacs calc?

(I looked in the Info pages, but was not able to tell if there a way to do this easily. I can use f h to compute the hypotenuse, but I can't figure out how to use that with points, or if Emacs has any first class notion of a point)

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    You can enter points as complex. abs((3,4))=>5 or abs(3+4i)=>5. For your example abs((x2,y2)-(x1,y1))=sqrt((x2-x1)^2+(y2-y1)^2)
    – gigiair
    Commented Feb 6, 2021 at 22:08
  • you can also enter points as array. abs([x2, y2] - [x1, y1])=>hypot(x2 - x1, y2 - y1)
    – gigiair
    Commented Feb 7, 2021 at 6:41

1 Answer 1

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You can represent points with complex numbers or vectors. The calc-abs (A) function returns the absolute value of a complex number or the Euclidean norm of a vector. For instance this is the trail trace which results from the calculus of the distance from [7 -2] to [4 2]

Emacs Calculator Trail
alg' [7, -2]
alg' [4, 2]
   - [-3, 4]
 abs 5
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  • You should expand your answer to include all of the details in your comments: that would make it much more useful.
    – NickD
    Commented Feb 7, 2021 at 20:57
  • The main point is that you can use the abs function for complex numbers or for vectors. I can't imagine that calculate a difference could create any difficulties. Points can be represented either with complex numbers or vectors, depending on the context.
    – gigiair
    Commented Feb 7, 2021 at 22:48
  • Thanks! You may be right, but IME, the more detailed the answer, the more helpful it is (not only for the OP, but also for future visitors).
    – NickD
    Commented Feb 7, 2021 at 22:55

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