Christopher2222

MaplePrimes Activity


These are answers submitted by Christopher2222

I think he means what are the points where the lines cross as viewed from the plot and how can it be calculated.

So I asked a different question above in this thread.  Because it was somewhat related I posted in the same thread however it is a somewhat different topic should I start it as a new thread?  It may be an obscured question because it follows a topic already answered. 

So anyone know why my Ellipse and Parabola produce a 4 point solution when only 2 exist?

Thanks for the allvalues however when I use allvalues with an ellipse and parabola I get 4 points to the solution.

e1:=x^2/2500+y^2/200=1;

e2:=y=x^2;

solve({e1,e2},{x,y});

allvalues(%);

Gives me 4 points.  There's only two in the solution.  Why does it poduce 4?  Maybe I'm not understanding allvalues or how Rootof works but maybe it's a bug? 

It shows 2 points in the negative y quadrants like it's finding the mirrored parabola intersect points which is clearly not part of the solution.  The e2 equation never gets to negative y values let alone even crossing the ellipse there so I'm not quite sure why the solution of the 2 equations gives me those points.  Does allvalues just give every possible combination of -'ve and +'ve x's and y's even if it's not an answer to the solution?

Thanks Acer, you are right.  The reality is quite higher than one thinks.  I should've calculated it out. 

Any other ways to produce a random array?

Yes, more explanation.  Ahmedluss, can you explain a little more what your code does.  Some of us do not have Matlab.  Yes Maple can export and convert code to Matlab but it's apparent and unfortunate Matlab doesn't convert to Maple.  My first quick guess at what your code does, is some sort of insect growth population scenario. 

Okay thanks.  I've submitted the SCR. 

I was so, sooo close to wipeing out my hard drive and starting again.  Phew!  It was one of those Aha, woohoo I found it, eureka!  type moments.  Gotta love those every now and then. 

"Why is everything so heavy in the future?  Is there something wrong with earth's gravitational pull?" 

Okay, I finally found the problem. 

If Tools->Options->Display->Typsetting level is set to Extended ...  Precision round screen display will not work. 

That is interface(displayprecision=10); 

evalf(10.5);

10.5

This is what was causing all the problems I was seeing.  If I set the Typsetting level to Maple standard, everything works fine. 

interface(displayprecision=10);

evalf(10.5);

10.5000000000

You can try it for yourself and see the results I was getting.  Can someone file a report for that?

Okay, thanks an older version works fine on my laptop and since it's working with yours there must be a problem at my end somewhere, probably my firewall or some conflict causing issues.  I'll reinstall and go from there, thanks for all the help. 

Thanks Jakubi, are you the only one not able to reproduce what I'm seeing?  I try exactly what you do and I still get 10.5

Just wondering if anyone else can reproduce what I'm seeing.

Okay, it works in classic worksheet mode but it doesn't work in the standard document interface mode. 

Thanks but that option doesn't appear to work.  I actually tried that earlier but that didn't change anything.

If I check the tools Precision box "Round screen display to ..."  with any number I still get 10.5 using evalf(10.5,10) and no following zeroes.

 

 

Thanks, yes that gives me what I want.  Does maple have a global option in the tools menu to set the number of decimal places after the decimal point?  Be a nice little addition if it doesn't. 

Some numbers won't display more digits.

Specified numbers in the numerator won't display more digits.  evalf(10.5,10) displays 10.5.  The only way to force maple to display more digits is to divide by 1.0 evalf(10.5/1.0,10) displays 10.50000000

Now if I want maple to only display 2 places after the decimal, specifying the number of digits won't work which brings me back to my original question in this thread. 

Okay I'll try to clear up what I mean.  What I want, is not to display it's current value but to display the expression with it's variables only.   

So if d=a*b+5/(3*h) and I've assigned values to a,b and h.  How do I get maple to display the original expression for d after the variables have been assigned?

Yes, thanks for the explanations.  It clears things up a lot except that glitch between the points -7 and -8 it's quite a huge jump and it does bug me.  Similar with the positive axis.  If I didn't know better to include a numpoints option and I was to hand that graph in to be marked I'd get zero. 

Maple should draw the graph without those jumps.  I think it's a glitch in the maple graph drawing that need to be fixed.

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