Three ways of inverting a matrix in RPN.
Let’s assume in M1 we have a 3x3 matrix. I took this example from Khan academy:
0 2 2
1 1 1
0 2 0
How we can invert it in RPN. I know of three different ways. Please update me if you know of any other!
M1 !to the stack with Enter
inv(1) !to express that it’ll use a single argument
M1 !to the stack with Enter
X–1 !much shorter than the other - but you still need to press the blue f key.
1 !ENTER
M1 !ENTER
/
The last two imply that the functions have different operation on different days types, and implies a CAS behind,or very good programming (let’s remember that the HP15c achieved routinely several of these feats, with its excellent use of all the keyboard keys for more than one function - and in some times 3 different functions, depending on the data it was operating on (number, complex or matrix) and how the “user” flag was set)