MTH 108 Trigonometric Functions of Acute Angles2FALL 2020
Definition 1 For an acute angle α,
b
a
c
α
csc α=c
a=hypotenuse
opposite leg
sec α=c
b=hypotenuse
adjacent leg
cot α=b
a=adjacent leg
opposite leg
The three trigonometric functions defined above are just reciprocals of the three others we defined
earlier:
csc α=1
sin αsec α=1
cos αcot α=1
tan α
Exercises
1. Given that sec γ= 3 find the exact values of the other five trigonometric functions.
2. Given that cot δ=2
√3find the exact values of the other five trigonometric functions.
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