HP 40gs - Manual (Page 197)

Computer Algebra System (CAS) 14-15
SUBST Substitute a value for a variable
SUBST has two parameters: an expression dependent on
a parameter, and an equality (parameter=substitute
value).
SUBST substitutes the specified value for the variable in
the expression.
Typing:
SUBST(A
2
+1,A=2)
gives:
TEXPAND Develop in terms of sine and cosine
TEXPAND has a trigonometric expression or
transcendental function as an argument.
TEXPAND develops this expression in terms of sin(x) and
cos(x).
Example
Typing:
TEXPAND(COS(X+Y))
gives:
Example
Typing:
TEXPAND(COS(3·X))
gives:
UNASSIGN Clear a variable
UNASSIGN is used to clear a variable, for example:
UNASSIGN(ABC)
2
2
1 +
y ( ) cos x ( ) cos y ( ) x ( ) sin ⋅ sin – ⋅
4 x ( )
3
cos 3 – x ( ) cos ⋅ ⋅
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