A function on the key D1
The keys D 1, D 2, and D 3 can each hold a function. To put the inverse hyperbolic sine on D 1, press 
, 
, and 
, then the keys of the function: 
, 
, and 
. D 1 then types that function. Test the stored function. Press , type 0.5, and press 
: 0.481211825.