Trig Functions - Texas Instruments TI-34 II Explorer Plus User Manual

Trig Functions

Overview
Students practice solving sine, cosine, and tangent
ratios, and solve problems involving trigonometric
ratios.
Introduction
Introduce the trigonometric ratios to students.
sin = opposite leg ¾ hypotenuse
cos = adjacent leg ¾ hypotenuse
tan = opposite leg ¾ adjacent leg
1. Have students find the trigonometric ratios for
the triangle using the above definitions. Round to
the nearest hundredth if necessary. (Use % ‚
for rounding.)
a. sin C
b. cos C
c. tan C
d. sin A
e. cos A
f. tan A
2. Have students find the value of each ratio using
the TI-34 Ö. Round to the nearest 10 thousandth.
a. sin 71°
b. tan 31°
c. cos 25°
3. Have students find the measure of each angle
using the TI-34 Ö. Round to the nearest degree.
a. sin B = 0.4567
b. cos A = 0.6758
c. tan C = 5.83
© 1999 T I
EXAS NSTRUMENTS
3 ¾ 5 = 0.6
4 ¾ 5 = 0.8
3 ¾ 4 = 0.75
4 ¾ 5 = 0.8
3 ¾ 5 = 0.6
4 ¾ 3 = 1.33
0.9455
0.6009
0.9063
27 degrees
47 degrees
80 degrees
I
NCORPORATED
Math Concepts
• multiplication
• division
• trigonometric
ratios
³ To set 2 decimal places:
1. Press % ‚.
F0123456789
2. Press 2 to select 2
decimal places and press
<.
³ To find sin 65°,
1. Press % ‚
2. Press % B <.
sin(
3. Enter 65, and press E
<.
sin(65)
³ To find A when sin A = 0.2756:
1. Press % ‚ 0.
2. Press % B " <.
sin
3. Enter 0.2756, and press
E <.
sin
TI-34 Û: A Guide for Teachers
Materials
• TI-34 Û
• pencil
• student activity
(page 12)
A
5
3
B C
4
.
4
0.9063
(
-1
¹ ¹
-1 (0.2756
16
10