Symbolic Manipulation 254
Note: Enter ln(x†y) instead of ln(xy); otherwise, xy is interpreted as a single variable
named xy.
Note: For ‚ or , press 8Ã or 8Â. You can also use 2I8 or 2G2 to
select them from a menu.
Using Substitutions vs. Defining a Variable
Using Substitutions vs. Defining a VariableUsing Substitutions vs. Defining a Variable
Using Substitutions vs. Defining a Variable
However, substitution is preferable for most cases because the variable is defined only
for the current calculation and does not accidentally affect later calculations.
Because sin
L1
(sin(q)) = q is not always valid, the
expression is not simplified.
With a constraint, the expression can be simplified.
In many cases, you can achieve the same
effect as a substitution by defining the
variable.
Substituting x=1 does not affect the next
calculation.
