HP 40gs User Manual page 219

SOLVE
Computer Algebra System (CAS)
then press ENTER. The following is then written to the
Equation Writer:
1
⎛ ⎞ AND y
-- -
x = –
⎝ ⎠
2
Solve equations
SOLVE has as two parameters:
(1) either an equality between two expressions, or a
single expression (in which case = 0 is implied), and
(2) the name of a variable.
SOLVE solves the equation in R in real mode and in C in
complex mode (ignoring REALASSUME).
Typing:
4
SOLVE(X -1=3,X)
gives, in real mode:
(x = −√2) OR (x = √2)
or, in complex mode:
(x = −√2) OR (x = √2) OR (x = −i · √2) OR (x = i√2)
Solve systems
SOLVE also enables you to solve a system of non-linear
equations, if they are polynomials. (If they are not
polynomials, use MSOLV in the HOME screen to get a
numerical solution.)
It is assumed that the various equations are of the form
expression = 0.
SOLVE has as arguments, the first members of the various
equations separated by AND, and the names of the
various variables separated by AND.
Typing:
2 2
SOLVE(X +Y
gives:
(x = 1) AND (y = −√2) OR (x = 1) AND (y = √2)
5
⎛ ⎞ AND z ⎛
-- -
= =
⎝ ⎠ ⎝
2
2
-3 AND X-Y +1,X AND Y)
1
⎞
-- -
–
⎠
2
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