Trigonometric Functions - Unit Circle Approach Worksheet Page 11
ADVERTISEMENT
1
2
3
4
5
6
7
8
9
10
11
1222
Objective 6:
Approximate the Value of a Trigonometric Function.
On a scientific calculator, SIN key is for the sine ratio, COS key is for the
cosine ratio, and TAN key is for the tangent ratio. To evaluate a
trigonometric ratio for a specific angle, you first want to be in the correct
mode. If the angle is in degree, then the calculator needs to be in degree
mode while if the angle is in radians, the calculator needs to be in radian
mode. Next, type in the angle and then hit the appropriate trigonometric
ratio. On some calculators, you might need to enter the trigonometric ratio
first and then the angle. For the secant, cosecant, and cotangent, we want
1
1
1
to use the following facts: sec( θ ) =
, csc( θ ) =
, cot( θ ) =
cos( θ )
sin( θ )
tan( θ )
Evaluate the following (round to three decimal places):
Ex. 8a
cos(26˚)
Ex. 8b
tan(78.3˚)
2
˚ )
Ex. 8c
sin(16
Ex. 8d
csc(56.11˚)
3
3 π
Ex. 8e
sec(1.2)
Ex. 8f
tan(
)
2
Solution:
a)
We put our calculator in degree mode, type 26 and hit the COS
key:
cos(26˚) = 0.8987… ≈ 0.899
b)
We put our calculator in degree mode, type 78.3 and hit the
TAN key: tan(78.3˚) = 4.8289… ≈ 4.829
2
c)
We put our calculator in degree mode, type 16
and hit the
3
2
˚ ) = 0.2868… ≈ 0.287
SIN key:
sin(16
3
d)
We put our calculator in degree mode, type 56.11 and hit
SIN key:
sin 56.11˚ = 0.8308…
Now, hit the 1/x key to take the reciprocal:
1
1
csc(56.11˚) =
=
= 1.2046… ≈ 1.205
sin(56.11)
0.8308...
e)
Since there is no degree mark on the angle, then the angle is in
radians. We put our calculator in radian mode, type 1.2 and hit
the COS key:
cos(1.2) = 0.3623…
Now, hit the 1/x key to take the reciprocal:
1
1
sec(1.2) =
=
= 2.7597… ≈ 2.760
cos(1.2)
0.3623...
ADVERTISEMENT
0 votes
Related Articles
Related forms
Related Categories
Parent category: Education