HP 39g hp 39g+ (39g & 40g)_mastering the hp 39g+_English_E_F2224-90010.pdf - Page 323

Solving equations, Simultaneous equations, will find the other two imaginary solutions

Page 323 highlights

E.g. 3 Solving equations Solve the equation x4 −1 = 3 , giving i) real solutions and ii) complex solutions. From any of the screen menus, access the CFG menu (see page 329) and ensure that Real mode is selected, as shown right. Now use the SOLVEVX function, typing: The SOLVEVX function assumes that the active variable is being used. The default active variable is X and if no = sign is included then the expression is assumed to be equal to zero. The related function of SOLVE has a second parameter which allows you to define the variable to be solved for. Changing to complex mode in the CFG menu will find the other two imaginary solutions: E.g. 4 Solving simultaneous equations Solve the following system of equations: x + x = y = −3 y −1 In the CAS, enter: LINSOLVE(X+Y+3 AND X-Y+1, X AND Y). Note that when entering the two equations you must highlight the first one before pressing AND (obtained via SHIFT (-)). Alternatively you can use X+Y=-3 AND X=Y-1 instead of the expressions. The result is: (X=-2) AND (Y=-1) LINSOLVE can be used for any number of simultaneous variables. Step by step mode will show the solution process using row manipulation of an augmented matrix. 323

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E.g. 3
Solving equations
Solve the equation
4
1
3
x
=
, giving i) real solutions and ii) complex solutions.
From any of the screen menus, access
the
CFG
menu (see page 329) and ensure
that
Real mode
is selected, as shown
right.
Now use the
SOLVEVX
function, typing:
The
SOLVEVX
function assumes that the active
variable is being used. The default active variable is
X
and if no
=
sign is included then the expression is
assumed to be equal to zero.
The related function
of
SOLVE
has a second parameter which allows
you to define the variable to be solved for.
Changing to complex mode in the
CFG
menu
will find the other two imaginary solutions:
E.g. 4
Solving simultaneous equations
Solve the following system of equations:
3
1
x
y
x
y
+
=−
=
In the CAS, enter:
LINSOLVE(X+Y+3 AND X±Y+1, X AND Y)
.
Note
that when entering the two equations you must highlight the first one before
pressing
AND
(obtained via
SHIFT (-)
).
Alternatively you can use
X+Y=-3 AND X=Y-1
instead of the expressions.
The result is:
(X=±2) AND (Y=±1)
LINSOLVE
can be used for any number of simultaneous variables.
Step by
step mode will show the solution process using row manipulation of an
augmented matrix.