HP 39GS hp 39gs_user's guide_English_E_HDPMG39AE13.pdf - Page 170

QUAD QUOTE | (where) Test functions < ≤ Solves quadratic expression=0 for variable and returns a new expression, where variable=newexpression. The result is a general solution that represents both positive and negative solutions by including the formal variable S1 to represent any sign: + or - . QUAD(expression, variable) Example QUAD((X-1)2-7,X) returns (2+s1*5.29150262213)/2 Encloses an expression that should not be evaluated numerically. QUOTE(expression) Examples QUOTE(SIN(45)) F1(X) stores the expression SIN(45) rather than the value of SIN(45). Another method is to enclose the expression in single quotes. For example, X^3+2*X F1(X) puts the expression X^3+2*X into F1(X) in the Function aplet. Evaluates expression where each given variable is set to the given value. Defines numeric evaluation of a symbolic expression. expression|(variable1=value1, variable2=value2,...) Example 3*(X+1)|(X=3) returns 12. The test functions are logical operators that always return either a 1 (true) or a 0 (false). Less than. Returns 1 if true, 0 if false. value1< value2 Less than or equal to. Returns 1 if true, 0 if false. value1≤ value2 13-18 Using mathematical functions