Texas Instruments Titanium TI-89, User Manual

Page: 730 / 977

Activities 727
Exploring cos(x) = sin(x)
This activity uses two methods to find where
cos(x) = sin(x)
for the values of
x
between 0
and 3
p
.
3. Use
rref( ) to
“row reduce” matrix
b
:
The result will have the identity matrix in
the first three columns and
a^ L 1
in the last
three columns.
Note:
Use the cursor in the history area to
scroll the result.
4. Solve for the value of
x
that will cause the
inverse of the matrix to be invalid.
Enter:
solve(getDenom(
2 ±
[1,4] )=0,x)
Result:
x=
L
70/17
Note:
Use the cursor in the history area to
scroll the result.