More Algebra with the TI-84 Plus Silver Edition
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© Texas Instruments, 2007
Equations of Lines
This section features the
Topics in Algebra 1
App for the TI-84 Plus Silver Edition.
Ax + By = C
Standard form — graph using
intercepts
y = mx + b
Slope-intercept form — graph using
m
and
(0,b)
y – y
1
= m(x – x
1
)
Point-slope form — graph using
m
and
(x
1
, y
1
)
Standard form example
Given
3x + 2y = 6,
find intercepts:
3(0) + 2y = 6
3x + 2(0) = 6
x
y
2y = 6
3x = 6
0
3
y = 3
x = 2
2
0
Point-slope form example
Given m=3 and (2,-3)
Equation
y – (-3) = 3(x-2)
y + 3 = 3x – 6
y = 3x – 9
Keystrokes
o ë ¬ Ñ π Æ q
_
Definition of Slope
This section uses the
Topics in Algebra 1
App for the TI-84 Plus Silver Edition
to help define slope.
m =
vertical change
=
rise
=
y
2
– y
1
horizontal change run x
2
– x
1
Quadratic Functions
This section features the
Conic Graphing
App for the TI-84 Plus Silver Edition.
Equation of a circle:
(x – H)
2
+ (y – k)
2
= R
2
Values are entered for the center and the radius. The
Conic Graphing
App
produces a circle you can now trace.
Equation of a parabola:
(x – H)
2
= 4P(y – k)
Values are entered for the vertex (H, K) and the distance (P) between
the directrix and the vertex. The
Conic Graphing
App produces a
parabola you can now trace.
The
Transformation Graphing
App allows you to see what happens to a
graph as you change its coefficient(s).
The Distance Formula
The Distance Formula is used to calculate the distance between two points.
d(P
1
, P
2
) =
√
(x
2
– x
1
)
2
+ (y
2
– y
1
)
2
Example:
Find the distances between the points
P
1
(2, 5) and
P
2
(-3, 1).
d(P
1
, P
2
) =
√
(-3 – 2)
2
+ (1 – 5)
2
=
√
(-5)
2
+ (-4)
2
=
√
25 + 16 =
√
41
≈
6.403
Keystrokes
- z
£
M
[ T Z E 6 \ D Y T R E 6 E b
≈
6.403
To draw the line segment between (-3, 1) and (2, 5) on your
TI-84 Plus Silver Edition:
y<
2:Line
M
¬ ¢ ¿ ¢ ¡ ¢ § Õ
