Integral on WP 34s (and others)

02212016, 10:11 PM
Post: #1




Integral on WP 34s (and others)
When taking integral of (8x^2 + 26x + 15)/(2x^2  x 15) from 5 to 0, I get out of domain error on the WP 34s. CASIO 9869gii and CLASSWIZ FX991EX also fail. They all do fine if the lower start point is very close to 5 such as 5.0001. After fiddling around, I came to guess that this is due to denominator being undefined at X=2.5, that one of the incremental dx' being added starts with 2.5
Is there an easy work around... I was just about to submit, and realized that I could test this thought easily by adding 2 integrals where 2.5 would not likely be a starting point...I.e, integral from 5 to 3 plus integral from 3 to 0. Works! My ~62 year old mind isn't gone yet! 

02222016, 07:29 AM
Post: #2




RE: Integral on WP 34s (and others)
(02212016 10:11 PM)lrdheat Wrote: When taking integral of (8x^2 + 26x + 15)/(2x^2  x 15) from 5 to 0, I get out of domain error on the WP 34s. CASIO 9869gii and CLASSWIZ FX991EX also fail. They all do fine if the lower start point is very close to 5 such as 5.0001. Sure. This way the (removable) singularity at x=–2,5 is (probably) not evaluated. This may happen with any integration method. (02212016 10:11 PM)lrdheat Wrote: I was just about to submit, and realized that I could test this thought easily by adding 2 integrals where 2.5 would not likely be a starting point...I.e, integral from 5 to 3 plus integral from 3 to 0. Another option: simplify the expression to (4x+3)/(x–3). Here the pole at x=3 is far beyond the integration limits. ;) Dieter 

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