MaplePrimes - answers and comments on Question, Plots with units

Removing units beforehand?

erik10 — Tue, 09 Feb 2010 20:45:26 Z

Maybe I need to redefine the dimensions without units and plot the graph and then put labels on manually:

> plot(A(t), t=0..100, labels=[t [[years]], A [[Bq]] ])

I can make it work this way, but it is annoying this is necessary ...

Regards, Erik V.

help...?

herclau — Wed, 10 Feb 2010 03:32:16 Z

restart;
T := 30:
A0 := 370000:
A := t-> A0*(1/2)^(t/T);
plot(A(t), t = 0 .. 100, A = 0 .. 400000,
 useunits = [Unit('years'), Unit('Bq')]);

http://www.mapleprimes.com/files/9494_units_graph.jpg

Right, but still it is

erik10 — Wed, 10 Feb 2010 04:34:46 Z

Right, but still it is annoying to have to strip off units to be able to make this plot, after having solved the first part of the exercise using units. Almost the same command lines need to be written twice. I simply don't understand why Maple can't handle this situation: It is clear and unambigious what units are being used for the independent variable t and the units for the dependent variabel A!

Regards, Erik V.

How about this?

Scott03 — Wed, 10 Feb 2010 23:37:17 Z

If you change the plot command from your original example to the following it seems to work in Maple 13.

plot(A(t*Unit(year)), t=0..100*Unit(year));

This will allow you to use your normal function that contains units, just that you specify the unit that is going to be used for the input variable.

Scott
Applicaiton Developer
Maplesoft

Thank you so much, Scott!

erik10 — Thu, 11 Feb 2010 05:26:44 Z

Thank you so much, Scott! You are right it works well. I am however still puzzled about the logic behind this syntax: When t runs from 0 to 100[[years]], then t[[years]] should run from 0 to100 [[years]]^2 in my World. Is Maple totally consistent here?Anyway I appreciate your answer!

Regards, Erik V.