Trig Functions - Texas Instruments TI-30X IIS 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-30X ÖS. 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-30X ÖS. Round to the nearest
degree.
a. sin B = 0.4567
b. cos A = 0.6758
c. tan C = 5.83
© 1999 T I I
EXAS NSTRUMENTS
3 ¾ 5 = 0.60
4 ¾ 5 = 0.80
3 ¾ 4 = 0.75
4 ¾ 5 = 0.80
3 ¾ 5 = 0.60
4 ¾ 3 = 1.33
0.9455
0.6009
0.9063
27 degrees
47 degrees
80 degrees
NCORPORATED
Math Concepts
• multiplication
• division
• trigonometric
ratios
A
3
B
³ To set 2 decimal places:
1. Press % ‚.
F0123456789
2. Press 2 to select 2
decimal places.
³ To find sin 71°:
1. Press >.
sin(
2. Enter 71; press E <.
sin(71)
0.945518576
3. Press % ‚ 4.
sin(71)
0.9455
³ To find B when sin B =0.4567:
1. Press % Z.
sin (
-1
2. Enter .4567; press E <.
sin (.4567)
-1
27.1744
3. Press % ‚
sin (.4567)
-1
TI-30X ÙS: A Guide for Teachers
Materials
• TI-30X ÙS
• pencil
student
activity
5
C
4
.
0
27.
10