The CAS can solve for a variable in a formula. Consider the motion equation
v
=
u
+
at
. Suppose that you want to solve this formula for time,
t
.
If you inspect the calculator keyboard, you will note that
x
,
y
,
z
and
t
have
dedicated keys. Other variables are entered by pressing the
ALPHA
key first. For
example, to access
a
, press
ALPHA
, then =
.
2.
Press
F2
, and select
1:solve(
.
Type
v
=
u
+
a× t
, then a comma,
then
t
followed by a close bracket
)
.
Tech Tip:
be sure to type the
multiplication operation between
the
a
and the
t
. Otherwise, the
CAS will treat
at
as a single
variable with the name
at
.
Press
ENTER
.
Tech Tip:
the new form of the formula is sometimes displayed in an unusual
manner.
Try solving other formulas, such as
V
=
π
r
2
h
for
r
.
Checking the solution to an equation
You can use the CAS to test a
solution to an equation. As an
example, test whether
x
= 2 is a
solution for the equation
3
x
– 1 = –7.
1.
Type 3
x
– 1 = –7. Then, press
the
|
(such that) key, followed by
x
= 2.
Press
ENTER
.
Note that the CAS returns a value of
false
. Hence,
x
= 2 is not a solution for the
equation. Try the check again with
x
= –2. Note that this time the CAS returns a
value of
true
. Hence,
x
= –2 is a solution.
Try checking a few more solutions for other equations.
