CHAPTER 3
Quadratic Functions
12
–
=
1
1
1
+
(
–
x
2
1
5
4
X
2
X
)
2
¡
(
2
X
)
À
=
=
=
3
+
¡
2
(–)
1
)
(
=
=
Determine the roots and axis of symmetry of the quadratic function
15
11
2
2
+
−
=
x
x
y
.
OPERATION
1
. Use the formula
a
ac
b
b
x
2
4
2
−
±
−
=
to determine the roots. While in
COMP
mode,
press
The first root is 3.
2
. To determine the second root, we use the
REPLAY
function.
Press
once to return to this display screen on right.
Press
numerous times until the cursor is below the ‘+’ sign.
Now
press
Followed by the key strokes
The second root is 2.5.
3
. To find the axis of symmetry, press
The axis of symmetry is
75
.
2
=
x
You may scroll through the last nine calculations by pressing the Replay function
.
Example 1
11+
À
( (-11)
2
-4X2X15
12
Ans
¡
(2X2)
3
11-
À
( (-11)
2
-4X2X15
10
Ans
¡
(2X2)
2.5
Ans+3
5.5
Ans
¡
2
2.75
11+
À
( (-11)
2
-4X2X15
12
