Texas Instruments manual More Algebra with the TI-84 Plus Silver Edition, Equations of Lines

More Algebra with the TI-84 Plus Silver Edition

Definition of Slope

The Distance Formula

This section uses theTopics in Algebra 1App for the TI-84 Plus Silver Edition

The Distance Formula is used to calculate the distance between two points.

to help define slope.

√

vertical change

rise

y

2

– y

1

d(P , P

) =

(x

– x

)2 + (y

2

– y

)2

m =

=

= x

1

2

2

1

1

horizontal change

run

2 – x1

Example: Find the distances between the pointsP1 (2, 5) and P2 (-3, 1).

√

= √

d(P , P

) =

(-3 – 2)2 + (1 – 5)2

(-5)2+ (-4)2

1

2

√

√

≈ 6.403

=

=

25 + 16

41

Keystrokes

-z £M [TZE6\DYTRE6Eb ≈ 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

Equations of Lines

This section features theTopics in Algebra App1 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 – y1 = m(x – x1)	Point-slope form — graph using m and (x1, y1)

Quadratic Functions

This section features theConic GraphingApp for the TI-84 Plus Silver Edition.

Equation of a circle: (x – H)2 + (y – k)2 = R2

Values are entered for the center and the radius. TheConic GraphingApp produces a circle you can now trace.

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

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 GraphingApp allows you to see what happens to a graph as you change its coefficient(s).

Keystrokes oë¬ÑπÆq_

© Texas Instruments, 2007 education.ti.com