Is_Constant - Texas Instruments TI-89 Developer's Manual

478

is_constant

Declaration: Boolean is_constant (EStackIndex i )
Category(ies): EStack Arithmetic
Description: Determines whether the expression indexed by i is a constant.
Inputs: i
Outputs: Returns TRUE if the expression indexed by i is free of all variables.
Otherwise returns FALSE. Examples include expressions composed of real
or unreal numbers, p ,
Assumptions: i indexes the top tag of an expression.
Side Effects: None
Availability: On AMS 2.02 and higher.
TI-89 / TI-92 Plus
Differences: None
See Also: can_be_approxed, is_complex_number, is_complex_float
Examples:
Boolean has_constant_term (EStackIndex i)
/* Returns TRUE if and only if the expression indexed by i has a zero
top-level constant term. */
{ while (! is0 (i))
if (is_constant (lead_term_index (i)))
return TRUE;
else
i = reductum_index (i);
return FALSE;
} /* end has_constant_term */
TI-89 / TI-92 Plus Developer Guide
Appendix A: System Routines — EStack Arithmetic
— Index to an expression.
, transfinites, true, false, and aggregates thereof.
e
Not for Distribution Beta Version January 26, 2001