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Unable to evaluate the following limit - teerasak - 06-02-2020 04:23 AM
I want to find the limit of the piece-wise function as follows: And here are the limit to find out The expected answer is -1 and -1/3 respectively. In the calculator with latest firmware (2020 01 21), it returns both limits to 0 which is not correct. In the emulator (as in this picture), it provides error message for the first one, but provide the correct answer for the second one. I verified this with TI Nspire, it provide the correct answer. could you please help fix this issue. RE: Unable to evaluate the following limit - parisse - 06-02-2020 02:03 PM
Can you give the input as a commandline? Pictures are nice but can not be copied/pasted. RE: Unable to evaluate the following limit - pinkman - 06-02-2020 02:57 PM
Definition of f1: f1(x):=PIECEWISE(x>1,x^2,(x>0) AND (x<=1),x-1,x<=0,0) The first limit: limit(f1(x^2),x,0,-1) The second limit: limit((f1(x-1))/(x+2),x,1,1) RE: Unable to evaluate the following limit - roadrunner - 06-02-2020 04:19 PM
In the simulator if you replace x^2 with x*x you get -1 for the first limit: limit(f1(x*x),x,0,-1) --> -1 -road RE: Unable to evaluate the following limit - victorvbc - 06-02-2020 05:35 PM
(06-02-2020 04:19 PM)roadrunner Wrote: In the simulator if you replace x^2 with x*x you get -1 for the first limit: Apparently the expression x^2<=0 simplifies to false (??). It works with x*x because the calculator doesn't automatically simplify that, so the limit takes the expression x*x<=0. RE: Unable to evaluate the following limit - parisse - 06-02-2020 06:08 PM
Thanks, this is now fixed in the source code. RE: Unable to evaluate the following limit - Gene - 06-02-2020 06:59 PM
By the way, I'm not a big PRIME user, but let me say off-topic a thank you to Bernard for all his work on the CAS of multiple HP machines. RE: Unable to evaluate the following limit - pinkman - 06-02-2020 10:33 PM
(06-02-2020 05:35 PM)victorvbc Wrote:(06-02-2020 04:19 PM)roadrunner Wrote: In the simulator if you replace x^2 with x*x you get -1 for the first limit: I don’t see it: how the 3rd condition could ever be true, even with x*x? RE: Unable to evaluate the following limit - victorvbc - 06-02-2020 10:50 PM
(06-02-2020 10:33 PM)pinkman Wrote: I don’t see it: how the 3rd condition could ever be true, even with x*x? It's true if x=0 RE: Unable to evaluate the following limit - teerasak - 06-03-2020 06:20 PM
Thank you parisse for fixing this. Thank you all for your help. RE: Unable to evaluate the following limit - pinkman - 06-03-2020 07:59 PM
(06-02-2020 10:50 PM)victorvbc Wrote:(06-02-2020 10:33 PM)pinkman Wrote: I don’t see it: how the 3rd condition could ever be true, even with x*x? Yes I know that, but I don’t understand what you did understand: Quote:Apparently the expression x^2<=0 simplifies to false (??).What simplification could lead the algorithm to understand x*x is more <=0 than x^2? RE: Unable to evaluate the following limit - victorvbc - 06-03-2020 08:14 PM
It's not about the expression itself, just that the calculator doesn't evaluate x*x<=0 to false, like it does with x^2<=0. Only if you simplify it. Here's a screenshot to illustrate my point: [attachment=8546] So my theory is the limit program doesn't have any problems with handling the inequality x*x<=0, but it can't handle the direct false from x^2<=0. That's why it throws the "Unable to handle when condition is false error". Edit: The correct simplification, of course, should just be x^2<=0. Because if x is zero (or some imaginary number), the resulting expression is true. RE: Unable to evaluate the following limit - pinkman - 06-03-2020 09:00 PM
Thanks, I didn’t get it, now I do! |