calc: Symbolic Mode
7.4.5 Symbolic Mode
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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.)
Info Catalog
calc: Infinite Mode
calc: Calculation Modes
calc: Matrix Mode