Place an equation on a Plot?

Questions
1

I want to place the equation on the plot. I make macros so it is easier to create plots. In this case y=x^3, with domain between [-5,5], and range between [-25, 25] The below script allows the user to enter the function and domain and range, and have the graph be generated automatically. This is just a small portion of the whole script.

The question is how to add a text version of the equation to the graph, and still use this template structure. I was able to do it with version 6, but not with version 7.

xL = -5
xR = 5

yT = 25

yB = -25

t = x^3

pp = Plot[Evaluate[t], {x, xL, xR}]

This is the complete script

clear[GraphSize]
clear[Tg]
clear[Te]
clear[Wg]
clear[We]
clear[Shifte]
clear[Sidee]
clear[xL]
clear[xR]
clear[yT]
clear[yB]
clear[t]
Null
Null
Null
Null
Null
Null
Null
Null
Null
Null
Null
Null
Null

GraphSize = 185
Tg = 6
Te = 6
Wg = Bold
We = Bold
Shifte = 0
Sidee = -1

Tope = 1

xL = -5`
xR = 5`
yT = 25
yB = -25

t = x^3

pp = Plot[Evaluate[t], {x, xL, xR}, 
   BaseStyle -> {FontSize -> Tg, FontWeight -> Wg}, 
   ImageSize -> {GraphSize, Automatic}, AspectRatio -> 1/1,  
   Ticks -> {{xL, xL + (xR - xL)/10, xL + 2 (xR - xL)/10, 
      xL + 3 (xR - xL)/10, xL + 4 (xR - xL)/10, xL + 5 (xR - xL)/10, 
      xL + 6 (xR - xL)/10, xL + 6 (xR - xL)/10, xL + 7 (xR - xL)/10, 
      xL + 8 (xR - xL)/10, xL + 9 (xR - xL)/10, xR}, {yB, 
      yB + (yT - yB)/10, yB + 2 (yT - yB)/10, yB + 3 (yT - yB)/10, 
      yB + 4 (yT - yB)/10, yB (yT - yB)/10, yB + 6 (yT - yB)/10, 
      yB + 7 (yT - yB)/10, yB + 8 (yT - yB)/10, yB (yT - yB)/10, yT}},
    GridLines -> {{xL, xL + (xR - xL)/10, xL + 2 (xR - xL)/10, 
      xL + 3 (xR - xL)/10, xL + 4 (xR - xL)/10, xL + 5 (xR - xL)/10, 
      xL + 6 (xR - xL)/10, xL + 6 (xR - xL)/10, xL + 7 (xR - xL)/10, 
      xL + 8 (xR - xL)/10, xL + 9 (xR - xL)/10, xR}, {yB - yB/100, 
      yB + (yT - yB)/10, yB + 2 (yT - yB)/10, yB + 3 (yT - yB)/10, 
      yB + 4 (yT - yB)/10, yB + 5 (yT - yB)/10, yB + 6 (yT - yB)/10, 
      yB + 7 (yT - yB)/10, yB + 8 (yT - yB)/10, yB + 9 (yT - yB)/10, 
      yT}},  GridLinesStyle -> Directive[Gray, Thin], 
   AxesStyle -> Arrowheads[{-0.05, 0.05}],  AxesLabel -> {"x", "y"}, 
   AxesOrigin -> {0, 0}, PlotRange -> {yB, yT}, 
   PlotStyle -> RGBColor[1, 0, 1]] /. 
  Line[x_] -> {Arrowheads[{-.05, .05}], Arrow[x]}
Export["F:\\OneEquation.eps", pp, "EPSTIFF"]
2

Here are a few ways:

Plot[t^3, {t, -5, 5}, Epilog -> Text[t^3, {3, 40}]]
Plot[Callout[t^3, t^3], {t, -5, 5}]
Plot[Legended[t^3, t^3], {t, -5, 5}]
Plot[t^3, {t, -5, 5}, PlotLabel -> t^3]
3

Try this one

Plot[t^3 && -25 <= t^3 <= 25, {t, -5, 5}]

4

The function is y=x^3, not t^3.

5

Your reply does not put the equation on the graph

6

The equation is y=x^3

Plot[t^3, {t, -5, 5}, Epilog → Text[t^3, {3, 40}]]

Does put t^3 on the graph, but does not put y=x^3 on the graph, and does not use the variable and table format.

7

Please avoid making multiple comments of the same meaning and please do invest some work into this yourself. You can easily modify the code for what you need:

Plot[t^3, {t, -5, 5}, Epilog -> Text[y == x^3, {3, 40}]]

Please also read forum rules and format code correctly: http://wolfr.am/READ-1ST

8

This is the original script

xL = -5
xR = 5

yT = 25

yB = -25

t = x^3

pp = Plot[Evaluate[t], {x, xL, xR}]

Your answer does not use variables. I know how to put the equation on the graph without using the variables, and I know how to do it using version 6.

9

@Peter Munro. please learn to format code properly on this forum: http://wolfr.am/READ-1ST

You keep posting non-formatted code.

10

Hi

Al code I post can be copied and pasted into version 7 and run

11

Plot[t^3 && -25 <= t^3 <= 25, {t, -5, 5}
, Epilog → Text[y == x^3, {3.2, 15}]
]

12

How does your answer relate to

xL = -5
xR = 5

yT = 25

yB = -25

t = x^3

pp = Plot[Evaluate[t], {x, xL, xR}]

13

Dear, @Peter Munro, you did not format code properly again as we asked you. It should be syntax-highlighted and framed, for example:

pp = Plot[Evaluate[t], {x, xL, xR}]

Please learn to format code properly on this forum: http://wolfr.am/READ-1ST

14

I am a bit confused, The Callout suggested by Gianluca seems to be what you requested – just change the variable slightly:

Plot[Callout[t, t], {x, xL, xR}]

or, with formatting

Plot[Callout[t, Style[t, Red, Medium]], {x, xL, xR}]

This gives the plot:

Plot.png
Plot.png360×199 5.49 KB

You can experiment with different formats, etc. (I would suggest that you try a variety before reposting).
[1]: http://community.wolfram.com//c/portal/getImageAttachment?filename=Plot.png&userId=599067

15

Now we are getting somewhere, but the question is how to put the equation on the graph. The equation would be either y=x^3 or y=x^3.

16

I think the misunderstanding is that an expression like t = x^3 is not an equation – it is an assignment – t is assigned the value of x^3. If you want the equation you must enter y == x^3 or if you already defined t, y == t. To put your expression on the plot in an equation form you need to do something like this:

eqn = y == t

Which assigns the equation y == t (which evaluates to y == x^3) to the variable, eqn.

Then plot it with

Plot[Callout[t, Style[eqn, Red, Medium]], {x, xL, xR}]

to get

plot2.png
plot2.png360×185 5.3 KB

17

If you insist on having = instead of ==, you can do it with HoldForm:

Plot[Callout[t, Style[HoldForm[y = t^3], Red, Medium]], {x, xL, xR}]
18

This is what I want, but Callout does not work with version 7, so I opted for PlotLabel for now. Later I will want to know how to use something like Legended command for graphing translations. In that case, I would want to have a have a legend to show the progression of translations from y=sinx to y=2sinx to y=2sin3x to y=2sin[3(x+pi/4)] to y=2sin[3(x+pi/4)]+1 This is for the eTutoring.com project. see http://www.etutoring.com/Free_Videos.php I need youtube subscribers, and/or donations. I am not making videos for a while while my right arm recovers from an injury. I have also added an image of the more detailed plot

xL = -5 

xR = 5

yT = 25

yB = -25

t = x^3

eqn = y == t

pp = Plot[t, {x, xL, xR}, PlotLabel -> eqn]
19

I have been using PlotLegend, but have had some difficulty adding the y= part. Do you know how to do that? Using the method for one equation did not work for multiple equations. I want to have a legend for translations.

clear[t]
clear[t1]
clear[t2]
clear[parenteqn]
clear[eqn1]
clear[eqn2]
clear[y]

t = x^3
t1 = (2 x)^3
t2 = 3 (2 x)^3
parenteqn = t
eqn1 = t1
eqn2 = t2

Plot[{t, t1, t2}, {x, -2, 2}, PlotLegend -> {parenteqn, eqn1, eqn2}, 
 LegendPosition -> {1, -.4}, LegendShadow -> None]
20

Peter,

Gianluca is correct. you keep using = instead of ==. if you want an expression like y = x^3 to print on the plot you MUST type it as y ==x^3 (Note there are two equal signs here!!!)

You need one small change to your posted code:

t = x^3
t1 = (2 x)^3
t2 = 3 (2 x)^3
parenteqn = y == t
eqn1 = y == t1
eqn2 = y == t2

Your plot command will now work as expected (in Version 7 – I can’t run it with my newer version).

Just so you understand, the expression:

parenteqn = y == t

means “define parenteqn to be the equation y == x^3” – the “t” gets substituted. This will now put “y=x^3” where you want it in the legend.