CHAPTER 1
Let’s Get Started
8
MODE
1
MODE
MODE
1
3
=
SHIFT
cos
-1
cos
0
•
8
˚
’”
3
=
6
0
–
Ans
˚
’”
Find all angles between
°
0 and
°
360 inclusive which satisfy the equation
38
.
0
cos
=
x
.
OPERATION
1
. First make sure your calculator is in
COMP/Deg
mode.
2
. Now, evaluate
38
.
0
cos
1
−
to determine
α
, the basic angle.
3
. Press
once and thus obtaining the basic angle
α
as approximately
'
40
67
°
.
4
. To determine the second angle, which lies in the fourth quadrant, press
`
Therefore the solutions are
'
40
67
°
and
'
20
292
°
, approximately.
Using similar operations as in Example 14, find all angles between
°
0
and
°
360
inclusive which
satisfy the equation
53
.
0
cos
=
x
.
cos
-1
0.38
67.66631734
Example 14
D
0
cos
-1
0.38
67
–
39
–
58.74
360-Ans
292.3336827
360-Ans
292
–
20
–
1.26