# I need help decorating this plot

I need to combine these plots of fdk (in blue) and RiemannXi (in orange) into one plot with all 3 pairs of axes in a form that allows labeling. I haven't been able to figure this out.

Edit---something to make this more interesting--- We can put Zeta[s] in as the third plot and legend. We get a crossover at {0,-1/2}. Awesome connections!

So grab one of the plots below and check it out. Edit2---new plot w/o legends Note: we constructed a unit-square within the 3 plots that connects them together.

fdk[s_] := 1/2 - 1/(2 s + 1)
{Plot[{fdk[s], \[Pi]^(-s/2) (-1 + s) Gamma[1 + s/2] Zeta[s]}, {s, -10,
10}, AspectRatio -> 1, AxesOrigin -> {1/2, 1/2}, Frame -> True],
Plot[{fdk[s], \[Pi]^(-s/2) (-1 + s) Gamma[1 + s/2] Zeta[s]}, {s, -10,
10}, AspectRatio -> 1, AxesOrigin -> {0, 0}, Frame -> True],
Plot[{fdk[s], \[Pi]^(-s/2) (-1 + s) Gamma[1 + s/2] Zeta[s]}, {s, -10,
10}, AspectRatio -> 1, AxesOrigin -> {-1/2, -1/2}, Frame -> True]}

• You simply need to write "Show@" in front of your expression: {Plot....} – Daniel Huber Nov 9 '20 at 17:02
• In v10.0 and later, RiemannXi is built-in. – Bob Hanlon Nov 9 '20 at 17:08
• @DanielHuber, Show doesn't combine the axes, so I need a way to make them lines. – Fred Kline Nov 9 '20 at 17:19
• @BobHanlon, the built-in function set the baseline which I didn't want. – Fred Kline Nov 9 '20 at 17:20
• I don't know what you mean by baseline. With v12.1.1, RiemannXi[s] evaluates to the expression that you are using and produces identical plots. – Bob Hanlon Nov 9 '20 at 17:24

Clear["Global*"]

fdk[s_] := 1/2 - 1/(2 s + 1)


To overlay the plots,

Plot[{fdk[s], RiemannXi[s]}, {s, -10, 10},
AspectRatio -> 1,
Axes -> False,
Frame -> True,
PlotLegends -> {fdk, RiemannXi},
Epilog -> ({Opacity[0.3, ColorData[2 # + 4]],
Tooltip[Line[{{-10, #}, {10, #}}], #],
Tooltip[Line[{{#, -1.25}, {#, 3}}], #]} & /@ (Range[-1, 1]/2))] However, this clutters up the plot. You can use Manipulate to select the origin location.

EDIT: Added Zeta[s] and used independent controls for x and y origins.

Manipulate[
Plot[{fdk[s], RiemannXi[s], Zeta[s]}, {s, -10, 10},
AspectRatio -> 1,
AxesOrigin -> {originx, originy},
Frame -> True, PlotLegends -> {fdk, RiemannXi, Zeta}],
Row[{Control@{{originx, 0, Style["x origin", 14, Bold]}, {-1/2, 0,
1/2}},
Spacer,
Control@{{originy, 0, Style["y origin", 14, Bold]}, {-1/2, 0,
1/2}}}]] • I haven't figured out how to shift the verticals one spot to the right: 0,1/2,1, without changing the horizontals. Also, as mentioned in the edits, I want Zeta inserted as the third plot. If you could change this post so I could grab the new code and the image, I'll throw a bounty your way. – Fred Kline Nov 11 '20 at 17:53

This looks like a job for GridLines:

gridlines = {#, #} & @
Thread[{{-1/2, 0, 1/2}, Directive[Thin, ColorData@#] & /@ Range}];

Plot[{fdk[s], RiemannXi[s]}, {s, -10, 10},
AspectRatio -> 1,
Axes -> False, Frame -> True,
PlotLegends -> "Expressions",
GridLines -> gridlines] Interactively position and add/remove (ALT + Click) grid lines using LocatorPane:

plot = Plot[{fdk[s], RiemannXi[s]}, {s, -10, 10}, AspectRatio -> 1,
Axes -> False, Frame -> True, PlotLegends -> "Expressions",
ImageSize -> Large];

DynamicModule[{pts = {#, #} & /@ {-1/2, 0, 1/2}},
LocatorPane[Dynamic[pts],
Dynamic @ Show[plot,
GridLines -> (Thread[{#, Directive[Thin, #] & /@
ColorData /@ Range[Length @ pts]}] & /@ Transpose[pts]),
` 