Answer:
A) sin θ = 3/5
B) tan θ = 3/4
C) csc θ = 5/3
D) sec θ = 5/4
E) cot θ = 4/3
Step-by-step explanation:
We are told that cos θ = 4/5
That θ is the acute angle of a right angle triangle.
To find the remaining trigonometric functions for angle θ, we need to find the 3rd side of the triangle.
Now, the identity cos θ means adjacent/hypotenuse.
Thus, adjacent side = 4
Hypotenuse = 5
Using pythagoras theorem, we can find the third side which is called opposite;
Opposite = √(5² - 4²)
Opposite = √(25 - 16)
Opposite = √9
Opposite = 3
A) sin θ
Trigonometric ratio for sin θ is opposite/hypotenuse. Thus;
sin θ = 3/5
B) tan θ
Trigonometric ratio for tan θ is opposite/adjacent. Thus;
tan θ = 3/4
C) csc θ
Trigonometric ratio for csc θ is 1/sin θ. Thus;
csc θ = 1/(3/5)
csc θ = 5/3
D) sec θ
Trigonometric ratio for sec θ is 1/cos θ. Thus;
sec θ = 1/(4/5)
sec θ = 5/4
E) cot θ
Trigonometric ratio for cot θ is 1/tan θ. Thus;
cot θ = 1/(3/4)
cot θ = 4/3
