 integration problem - Printable Version +- HP Forums (https://www.hpmuseum.org/forum) +-- Forum: HP Calculators (and very old HP Computers) (/forum-3.html) +--- Forum: HP Prime (/forum-5.html) +--- Thread: integration problem (/thread-8063.html) integration problem - leprechaun - 03-30-2017 09:00 AM I have a simple question about doing calculations. I suppose it is a simple one, or to be more precise two questions. Question one. If I use the "x t phi n" KEY on the android app of the prime it gives an x. If I do so on the virtual prime it says n.The physical prime is on the x side again. Can someone explain the n on the virtual prime to me? I tried deleting the cas vars. Question two. If I want to build a table like int(sin(x), start, pi/2) == factor*int(sin(x),0,pi/2), where factor is in the range from 0..1. How would I do that best? Hope the task is clear: a table of start angles resulting in an equidistant, increasing area under the sin-curve. Thanks a lot P.S. even more problems. integral(SIN(x)dx,0,pi) = approx(-180*COS(pi)/pi + 180/pi) a b/c -> 86.11E-3 on the physical prime (!) integral(SIN(n)dn,0,pi) = 2 on the virtual prime (n because of question 1) integral(SIN(x)dx,0,pi) = 2 on the android app What is happening on the physical prime?? RE: integration problem - Arno K - 03-30-2017 09:38 AM Quote:integral(SIN(x)dx,0,pi) = approx(-180*COS(pi)/pi + 180/pi) a b/c -> 86.11E-3 on the physical prime (!) because your angle mode is set to degrees instead of radians which you should use for calculus tasks. Quote:integral(SIN(n)dn,0,pi) = 2 on the virtual prime (n because of question 1) because your active application is Sequence, this x...key changes its behaviour according to that. Your table can easily be made using makelist :MAKELIST(int(sin(x),x,0,t),t,0,PI,pi/5). Arno RE: integration problem - grsbanks - 03-30-2017 11:01 AM (03-30-2017 09:00 AM)leprechaun Wrote:  Question one. If I use the "x t phi n" KEY on the android app of the prime it gives an x. If I do so on the virtual prime it says n. Is the active App on the physical Prime the same as on the Android Prime? Have a look at what's in the title bar at the top of the display. The character actually typed by the "x t theta n" key depends on the active app. RE: integration problem - leprechaun - 03-30-2017 11:10 AM great answers. Thank you very much!