Error when integrating absolute value

[LCieParagon]

(12-06-2019 06:55 PM)Aries Wrote:  Same result (9) here with CX II

This is the correct answer. The HP Prime provides 3 as an answer, which is obviously not correct. If you were to approximate the volume with say 10000 rectangular prisms, (I wrote a MATLAB script to do this) you will receive 9 as well.

I'm not sure why integrating absolute value and trigonometric functions provide such wrong answers. Hopefully this is addressed.