HP Prime Miscalculating

[Vtile]

The key here what none seems to take account is point were the calculator in approximation mode or in exact mode.

The given near zero answer is (approximately)correct if the calculator were approximation mode.

The given near zero answer is totally incorrect if the calculator were in exact mode.

The problem is logical not mathematical.

If the calculator is in exact mode set by user the CAS should behave according to that, while it is mathematically unorthodox solving answers like if user were using exact representation of given value instead of decimal value. In other words calculators CAS should expand (with silence or noting that "Unorthodox numerical format detected correcting user careless behaviour") the floating points to (36/10)²−4×(324/100) even if the user were typing the numbers in decimal format.

It is behaviour logic, coming from the user set logic rule called aprox/exact mode, not math in this case..

A engineers point of view.

Edit: HP 50g calculates it correctly both in aprox and exact with or without XQ command used (yep, I did RTFM to check the flag usage now when I know such command exist ) Tiny elements on and all xxxflows to error.

Code:

3: Rev #2.15
2: (3.600^2)-3.2400E0-4
1: 0.0000E0