Schivnorr

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14 years, 31 days

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These are Posts that have been published by Schivnorr

This first situation may or may not be a bug.

 

restart;

Student[Calculus1][CriticalPoints](x^2, x=-2..2);

interval := -2..2;

Student[Calculus1][CriticalPoints](x^2, x=-2..2);

Student[Calculus1][CriticalPoints](x^2, x=interval);

 

Notice the change in output when the variable "interval" has a value.

The second situation is definitely a big problem:

restart;

ode1:= diff(y(x),x) = y(x)*(y(x)-1)*x;
ode2:= diff(y(x),x) = y(x)*(y(x)-1)*(x-a);

I'm trying to do some differential geomery calculations and they are becoming outrageously large.  I'd like to use Maple's differential geometry package (tensor package), but it seems incapable of performing the calculations in an arbitrary number of dimensionis (i.e. with a fixed but arbitrary number of dimensions).  Does anyone know of a good package or tool to use for such work?

 

Hello everbody.  It's been a while.  I apologize for such a long absence.  Life gets busy, and I think we all know how that can be...

 

We hadn't been using Maple 12 for a full hour before we found a major bug.  To see / reproduce this error:

 

It's nice that the plot command tries to warn the users about incorrect inputs: [> plot(sin, x=4..6); Error, (in plot) invalid plotting of procedures, perhaps you mean plot(sin, 4 .. 6) [> plot([cos,sin], x=4..6); Error, (in plot) invalid plotting of procedures, perhaps you mean plot([cos, sin], 4 .. 6) However, there is a shortcoming that I suggest should be fixed: These lines produce a warning and an incorrect plot [> plot([cos,sin(x)], 4..6); [> plot([cos(x),sin], 4..6); [> plot([cos(x),sin(x)], 4..6); Whereas these lines produce no warning and an incorrect plot
Below is a link to a file I uploaded showing an example of using assigning the value obtained from eval() to a variable and then using evalf() versus using eval() inside of evalf(). The fact that there is some difference is not surprising; it's the sheer amount of difference that amazes me--up to 100%! Do also note that the difference "settle down" over time, which is to be expected. View 413_odd_rounding_example.mw on MapleNet or
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