Texas Instruments Voyage 200, User Manual

Page: 805 / 1008

Appendix A: Functions and Instructions 807
DelType
CATALOG
DelType
var_type
Deletes all unlocked variables of the type
specified by
var_type .
Note: Possible values for
var_type
are:
ASM, DATA, EXPR, FUNC, GDB, LIST, MAT, PIC,
PRGM, STR, TEXT, AppVar_type_name, All.
Deltype “LIST”
¸
Done
DelVar
CATALOG
DelVar
var1
[ ,
var2
] [ ,
var3
] ...
Deletes the specified variables from memory.
2
!
a
¸
2
(a+2)^2
¸
16
DelVar a
¸
Done
(a+2)^2
¸
(a + 2)
ñ
deSolve()
MATH/Calculus menu
deSolve(
1stOr2ndOrderOde
,
independentVar
,
dependentVar
)
⇒ ⇒ ⇒ ⇒
a general solution
Returns an equation that explicitly or implicitly
specifies a general solution to the 1st- or 2nd-
order ordinary differential equation (ODE). In the
ODE:
•
Use a prime symbol ( ' , press
2
È
) to
denote the 1st derivative of the dependent
variable with respect to the independent
variable.
•
Use two prime symbols to denote the
corresponding second derivative.
The ' symbol is used for derivatives within
deSolve()
only. In other cases, use
d
( )
.
The general solution of a 1st-order equation
contains an arbitrary constant of the form @
k
,
where
k
is an integer suffix from 1 through 255.
The suffix resets to 1 when you use
ClrHome
or
ƒ
8: Clear Home
. The solution of a 2nd-order
equation contains two such constants.
Note: To type a prime symbol ( ' ), press 2
È
.
deSolve(y''+2y'+y=x^2,x,y)
¸
y=(@1
ø
x+@2)
ø e
ë
x
+x
ñ ì
4
ø
x+6
right(ans(1))
!
temp
¸
(@1
ø
x+@2)
ø e
ë
x
+x
ñ ì
4
ø
x+6
d
(temp,x,2)+2
ù
d
(temp,x)+temp
ì
x^2
¸
0
DelVar temp
¸
Done
Apply
solve()
to an implicit solution if you want
to try to convert it to one or more equivalent
explicit solutions.
deSolve(y'=(cos(y))^2
ù
x,x,y)
¸
tan(y)=
x
ñ
2
+@3
When comparing your results with textbook or
manual solutions, be aware that different
methods introduce arbitrary constants at different
points in the calculation, which may produce
different general solutions. solve(ans(1),y)
¸
y=tan
ê
(
x
ñ
+2
ø
@3
2
)
+@n1
ø p
Note: To type an @ symbol, press:
2
R
ans(1)|@3=c
ì
1 and @n1=0
¸
y=tan
ê
(
x
ñ
+2
ø
(c
ì
1)
2
)
deSolve(
1stOrderOde
and
initialCondition
,
independentVar
,
dependentVar
)
⇒ ⇒ ⇒ ⇒
a particular solution
Returns a particular solution that satisfies
1stOrderOde
and
initialCondition
. This is usually
sin(y)=(y
ù e
^(x)+cos(y))y'
!
ode
¸
sin(y)=(
e x ø
y+cos(y))
ø
y'
deSolve(ode and y(0)=0,x,y)
!
soln
¸