## 7671 Reputation

17 years, 242 days

## Odd behavior of DEplot...

Maple 18

In the attached Maple worksheet I attempt to plot the solution of an initial value problem for a first order ODE.  DEplot fails with a cryptic message.  Strangely enough, if I give the "arrows=none" option to DEplot, it produces the correct plot!

I see this behavior in Maple 17 and 18.

Maple 11, however, works fine with or without the "arrows=none" option.

Is there an explanation for this or is it a bug?

DEplot-bug.mw

## How to explain this behavior of seq()?...

Maple

The following works as intended:

restart;
diff(x^7, x\$i):
seq(%, i=0..7);

Combining the two commands into one, however, does not work:

restart;
seq(diff(x^7, x\$i), i=0..7);

Error, invalid input: diff expects 2 or more arguments, but received 1

How does one explane this?  I was unable to find the reason by looking at the help page for seq().

## How to simplify this?...

Maple

The expression

A := (a/u*(y*exp(-y) - x*exp(-x))/(y-x) + b/u) / (c/u + d/u);

is obviously equivalent to

I typed the latter by hand since I don't know how to do it in Maple.  Is there a trick to get Maple to do the simplification as shown?

## Setting the help window's default zoom?...

Maple

My eyesight is not what it used to be, so I would like to maginfy Maple's help window with a zoom factor of 150%.   I know how to do that by hitting Ctrl-F4.  My question is: Is it possible to save that setting somehow so that help is displayed at 150% by default?

Aside: The option Tools->Options->Interface->Default Zoom does not seem to do what I want.  For one thing, it sets the zoom factor of the main worksheet which I don't want to change.  For another thing, it affects the zoom factor of the help window in a rather mysterious way.  For instance, if I set Default Zoom to 400%, then the main window is indeed zoomed by 400% but the help window is zoomed by only 200%.

Platform: Maple 18 on Linux

## How to get lighting parameters from a 3D...

Maple

I have produded a 3D plot where I have used the graphic's lighting->user GUI to set the light color, direction, and ambient lighting to my liking.

I would like to save the lighting parameters so that I can reproduce the identical lighting in other plots.  I see no way of reading off the lighting parameters from the GUI.  I tried to "lprint(myplot)" to see if it contains that information but apparently it doesn't.

So my question is: Is there a way to retrieve the lighting parameters from a 3D plot?

--

Rouben Rostamian

 First 13 14 15 Page 15 of 15
﻿