Answer:
<em>Answer: C</em>
Step-by-step explanation:
<u>The Cosine Function</u>
The graph of a cosine function is a sinusoid that starts at its maximum value of 1 at x=0 and takes x=2π radians to complete a full cycle. The function of the parent cosine function is:

Both the amplitude A and the angular frequency w of a cosine can be modeled by the function

The graph of the cosine function shown in the figure has an amplitude of A=3 and it completes a full cycle at x=π/2, thus:

Thus:

Therefore, the equation of the sinusoid is:

Answer: C
 
        
                    
             
        
        
        
Answer correct or incorrect
 
        
        
        
Step-by-step explanation:
Use SOH-CAH-TOA.
Sine = Opposite / Hypotenuse
Cosine = Adjacent / Hypotenuse
Tangent = Opposite / Adjacent
Let's start with #12.  The hypotenuse is 18.  The side adjacent to ∠B is 6.  Since we have the adjacent side and hypotenuse, we should use cosine.
cos B = 6/18
Solving for B:
B = cos⁻¹(6/18)
Using a calculator:
B ≈ 70.5°
Now let's do #14.  The side adjacent to ∠B is 19, and the side opposite of ∠B is 22.  Since we have the adjacent side and opposite side, we should use tangent.
tan B = 22/19
Solving for B:
B = tan⁻¹(22/19)
Using a calculator:
B ≈ 49.2°