[BUG] CAS looping forever

03082014, 06:13 PM
(This post was last modified: 03082014 06:21 PM by Tugdual.)
Post: #1




[BUG] CAS looping forever
Trying to integrate using radians:
$$\int_{3}^{5}\tan (\sin \left ( x \right )+\ln \left ( \left  x \right  \right ))dx$$ Home returns 2.067... CAS loops forever on emulator and freezes the physical device. Edit: Epsilon was super small, like 1e12 which is the default value. I tried to change Epsilon to 0.01 and got a message "Restoring epsilon to 1e6 from 0.01". Loops again... 

03082014, 07:07 PM
(This post was last modified: 03082014 07:25 PM by Mark Hardman.)
Post: #2




RE: [BUG] CAS looping forever
(03082014 06:13 PM)Tugdual Wrote: Trying to integrate using radians: Just taking the indefinite integral of \(\int \tan \left ( \sin \left ( x \right ) \right ) dx\) produces a result that is 122,286 characters long! integrate((5*sin(x)+6*e^(cos(x)*((cos(x))²(sin(x))²1)/((cos(x))²+(sin(x))²)+sin(x)*2*cos(x)*sin(x)/((cos(x))²+(sin(x))²))*sin( ...<SNIP>... +(sin(x))²)))²216*(cos(x))²*(sin(x))²+132*cos(x)^4+132*sin(x)^4+24*(cos(x))²24*(sin(x))²+2),x) Impressive if the result is correct. Mark Hardman Ceci n'est pas une signature. 

03082014, 07:33 PM
Post: #3




RE: [BUG] CAS looping forever
It does not have an antiderivative that can be expressed with elementary function therefore you must do numeric integration using approx boundaries. I probably should add a check in the autosimplification function, if you set it to none you get the unevaluated "exact" answers without problems.


03082014, 08:21 PM
Post: #4




RE: [BUG] CAS looping forever  
03082014, 08:46 PM
(This post was last modified: 03082014 08:46 PM by Mark Hardman.)
Post: #5




RE: [BUG] CAS looping forever
(03082014 08:21 PM)Tugdual Wrote: How do you do "an integration using approx boudaries"? He means that you should specify real values for the limits of integration: $$\int_{3.0}^{5.0}\tan (\sin \left ( x \right )+\ln \left ( \left  x \right  \right ))dx$$ This gives the same approximation you get in Home mode (2.06725680644). Mark Hardman Ceci n'est pas une signature. 

03082014, 11:09 PM
Post: #6




RE: [BUG] CAS looping forever
I get the same results here, when using approximate (real) boundaries.
However the time to compute the same result is quite different between Home and CAS environments: Home takes about 2 seconds, and CAS answer is instantaneous ! So the Prime gives the same apparent result, but it is using different algorithms, where one takes significant more time than the other? Jose Mesquita RadioMuseum.org member 

« Next Oldest  Next Newest »

User(s) browsing this thread: 1 Guest(s)