puzzled by key in home vs cas for sin(45) degrees - 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: puzzled by key in home vs cas for sin(45) degrees (/thread-17245.html) puzzled by key in home vs cas for sin(45) degrees - Liamtoh Resu - 07-14-2021 01:08 AM I am puzzled by: In home mode , evaluating SIN(45) gives three answers when cycling it with the key: the irrational fraction, a decimal approximation, and a fractional approximation. In cas mode, evaluating sin(45) gives the irrational fraction at first. Cycling the key alternates between the decimal approximation and the fractional approximation. I would have thought in cas mode then key would also show the irrational fraction as well. Any feed back would be appreciated. Thanks. RE: puzzled by key in home vs cas for sin(45) degrees - Joe Horn - 07-14-2021 04:10 AM (07-14-2021 01:08 AM)Liamtoh Resu Wrote:  I am puzzled by: In home mode , evaluating SIN(45) gives three answers when cycling it with the key: the irrational fraction, a decimal approximation, and a fractional approximation. In cas mode, evaluating sin(45) gives the irrational fraction at first. Cycling the key alternates between the decimal approximation and the fractional approximation. I would have thought in cas mode then key would also show the irrational fraction as well. Any feed back would be appreciated. Thanks. As you noticed, the [a b/c] key behaves very differently in Home and in CAS modes. This is intentional. In Home mode, that key only toggles between multiple representations of the most recent result (or the selected result) as a display fiction, without actually changing the result or generating a new result. In CAS mode, however, that key either performs the approx() function or the exact() function on the most recent result, thereby generating an entirely new result. Press [Help] [Keys] [a b/c] to see the built-in explanation of the above distinction. "If Home and CAS behaved the same way, there would be no need to have both of them. They are different tools for different tasks." -- Joe Horn RE: puzzled by key in home vs cas for sin(45) degrees - Albert Chan - 07-14-2021 09:27 AM FYI, the irrational fraction is a guess, from decimal float. (SIN(45) - 35E-12) to (SIN(45) + 34E-12) all guessed irrational fraction √(1/2)