Calculations are normally
performed numerically wherever possible. For example, the
calc-sqrt command, or sqrt function in
an algebraic expression, produces a numeric answer if the
argument is a number or a symbolic expression if the argument is
an expression: 2 Q pushes 1.4142 but <'>
x+1 <RET> Q pushes ‘sqrt(x+1)’.
In Symbolic
mode, controlled by the m s
(calc-symbolic-mode) command, functions which would
produce inexact, irrational results are left in symbolic form.
Thus 16 Q pushes 4, but 2 Q pushes
‘sqrt(2)’.
The shift-N
(calc-eval-num) command evaluates numerically the
expression at the top of the stack, by temporarily disabling
calc-symbolic-mode and executing =
(calc-evaluate). Given a numeric prefix argument, it
also sets the floating-point precision to the specified value for
the duration of the command.
To evaluate a formula numerically without expanding the
variables it contains, you can use the key sequence m s a v
m s (this uses calc-alg-evaluate, which
resimplifies but doesn't evaluate variables.)