Why it's not possible to request a CAS var in a program on HP Prime ? INPUT( only accepts numerical var :(
" INPUT( only accepts numerical var :( "
You can enter alpha value between ""
and how to tranform it into an algebric expression ? EXPR("4*X+1") just calculates the expression with the X value. Impossible to work and use CAS commands with the expression 4*X+1 in a program :(