Displaying coordinates on graph

Questions
,
1

Dear Members,
I require that the coordinates display on the graph as the intersection move dynamically.
Thank you for your usual help.

Manipulate[ContourPlot[{
   -5 v1 - 82 v2 == (v3 - 522),
   -1.25 v1 - 4.45 v2 == (v4 - 263)},
  {v1, 10, 50},
  {v2, 2, 5},
  PlotLegends -> Placed[{"a58", "a60"}, Above],
  FrameLabel -> {"X", "Y"},
  Axes -> True,
  Frame -> True],
 {{v3, 94, "a58"}, 6, 892, Appearance -> "Open"},
 {{v4, 165, "a60"}, 165, 270, Appearance -> "Open"},
 ControlPlacement -> Left]
2

Manipulate[
intersection = NSolveValues[{-5 x - 82 y == v3 - 522, -1.25 x - 4.45 y == v4 - 263}, {x, y}];
ContourPlot[
{-5 v1 - 82 v2 == (v3 - 522), -1.25 v1 - 4.45 v2 == (v4 - 263)},
{v1, 10, 50}, {v2, 2, 5},
PlotLegends → Placed[{“a58”, “a60”}, Above], FrameLabel → {“X”, “Y”},
Axes → True, Frame → True, PlotLabel → intersection
],
{{v3, 94, “a58”}, 6, 892, Appearance → “Open”},
{{v4, 165, “a60”}, 165, 270, Appearance → “Open”},
{intersection, None},
ControlPlacement → Left
]

3

Dear Sir,
Thank you for your response
I am trying to get something like the example image attached.
The coordinates can be either on the graph itself or on the left

9845.JPG
9845.JPG652×454 20.4 KB

9845.JPG
9845.JPG652×454 20.4 KB

4

OK, here is a version with coordinates at the left

Manipulate[
 	isect = {x, y} /. NSolve[{-5 x - 82 y == v3 - 522, -1.25 x - 4.45 y == v4 - 263}, {x, y}] // First;
 	coords = Grid[{{"X:", First@isect}, {"Y:", Last@isect}}, Alignment -> "."];
 	ContourPlot[
  		{-5 v1 - 82 v2 == (v3 - 522), -1.25 v1 - 4.45 v2 == (v4 - 263)},
  		{v1, 10, 50}, {v2, 2, 5},
  		PlotLegends -> Placed[{"a58", "a60"}, Above], FrameLabel -> {"X", "Y"},
  		Axes -> True, Frame -> True
  	],
 	{{v3, 94, "a58"}, 6, 892, Appearance -> "Open"},
 	{{v4, 165, "a60"}, 165, 270, Appearance -> "Open"},
 	{isect, None}, {coords, None},
 	Delimiter, Spacer@{0, 50},
 	Style[Dynamic[coords], 14] // Framed,
 	ControlPlacement -> Left, TrackedSymbols :> {v3, v4}
 ]
5

Dear Sir,
Thank you very much.
Grateful for your help.

6

Dear Sir,
Trust you are well.
In the previous program, I’ve been trying to set the solution to be displayed at 3 decimal places.
I’ve tried with:

NSolve[{-5 x - 82 y == v3 - 522, -1.25 x - 4.45 y == v4 - 263}, {x, 
  y}, Reals, 3]

NSolve[{-5 x - 82 y == v3 - 522, -1.25 x - 4.45 y == v4 - 263}, {x, 
  y}, WorkingPrecision -> 3]

But none are giving the output at 3 decimal places.
Grateful for your time and your help.
Thanks and regards.

7

You can use NumberForm. e.g.

With[{v3 = 6, v4 = 190}, 
   {x, y} /. 
    NSolve[{-5 x - 82 y == v3 - 522, -1.25 x - 4.45 y == v4 - 263}, {x, y}]] // First // 
    NumberForm[#, {Infinity, 3}] &
(* {45.979, 3.489} *)

As with most form wrappers, the result cannot be used in subsequent computations, it is for display only. So used NumberForm on First@isect and Last@isect.

8

Thanks for prompt reply Prof.
However as I included in the program, It doesn’t working.
Kindly revert me for resolve. Thanks.

Manipulate[With[{v3 = 6, v4 = 190},
  isect = {x, y} /.
      NSolve[
       {-5 x - 82 y == v3 - 522,
        -1.25 x - 4.45 y == v4 - 263},
       {x, y}] // First // NumberForm[#, {Infinity, 2}] &;
  coords = 
   Grid[{{"X:", First@isect}, {"Y:", Last@isect}}, Alignment -> "."]];
 
 ContourPlot[
  {-5 v1 - 82 v2 == (v3 - 522),
   -1.25 v1 - 4.45 v2 == (v4 - 263)},
  {v1, 10, 50}, {v2, 2, 5},
  PlotLegends -> Placed[{"a58", "a60"}, Above],
  FrameLabel -> {"X", "Y"},
  Axes -> True, Frame -> True],
 {{v3, 94, "a58"}, 6, 892, Appearance -> "Open"},
 {{v4, 165, "a60"}, 165, 270, Appearance -> "Open"},
 {isect, None}, {coords, None},
 Delimiter, Spacer@{0, 50},
 Style[Dynamic[coords], 18] // Framed, ControlPlacement -> Left]
9

Try the code below. Besides the 3 decimals issue I have also moved the coordinate display to the center, should you think that looks better.

Manipulate[
 	isect = {x, y} /. NSolve[{-5 x - 82 y == v3 - 522, -1.25 x - 4.45 y == v4 - 263}, {x, y}] // First;
 	isect = NumberForm[#, {Infinity, 3}] & /@ isect;
 	coords = Grid[{{"X:", First@isect}, {"Y:", Last@isect}}, Alignment -> "."];
 	ContourPlot[
  		{-5 v1 - 82 v2 == (v3 - 522), -1.25 v1 - 4.45 v2 == (v4 - 263)},
  		{v1, 10, 50}, {v2, 2, 5},
  		PlotLegends -> Placed[{"a58", "a60"}, Above], FrameLabel -> {"X", "Y"},
  		Axes -> True, Frame -> True
  	],
 	{{v3, 94, "a58"}, 6, 892, Appearance -> "Open"},
 	{{v4, 165, "a60"}, 165, 270, Appearance -> "Open"},
 	{isect, None}, {coords, None},
 	Delimiter, Spacer@{0, 50},
 	Item[Style[Dynamic[coords], 14] // Framed, Alignment -> Center],
 	ControlPlacement -> Left, TrackedSymbols :> {v3, v4}
 ]
10

num = NumberForm[#, {Infinity, 3}] &;

Manipulate[
 isect = {x, y} /. 
    NSolve[{-5 x - 82 y == v3 - 522, -1.25 x - 4.45 y == 
       v4 - 263}, {x, y}] // First;
 coords = Grid[Thread[{{"X:", "Y:"}, num /@ isect}], Alignment -> "."];
 
 ContourPlot[
  {-5 v1 - 82 v2 == (v3 - 522), -1.25 v1 - 4.45 v2 == (v4 - 263)},
  {v1, 10, 50}, {v2, 2, 5},
  PlotLegends -> Placed[{"a58", "a60"}, Above], 
  FrameLabel -> {"X", "Y"}, Axes -> True, Frame -> True, 
  Epilog -> 
   First@ListPlot[{Callout[isect, coords]}, 
     PlotRange -> {{10, 50}, {2, 5}}, 
     PlotStyle -> Directive[Large, Red]]]
 ,
 {{v3, 94, "a58"}, 6, 892, Appearance -> "Open"},
 {{v4, 165, "a60"}, 165, 270, Appearance -> "Open"},
 {isect, None},
 {coords, None},
 Delimiter,
 Spacer@{0, 50}, 
 Item[Style[Dynamic[coords], 14] // Framed, Alignment -> Center],
 ControlPlacement -> Left,
 TrackedSymbols :> {v3, v4}]

Using Epilog with Callout you can have your coords in the plot

callout.png
callout.png661×467 13.4 KB

11

Dear Prof. Milton,
Thank you very much. Works wonderfully

12

Dear Prof. Froeling,
Thank you very much for your suggestion. I’ll implement same in the code.