Answer:
Answer: C
Step-by-step explanation:
The Cosine Function
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:
[tex]y=\cos x[/tex]
Both the amplitude A and the angular frequency w of a cosine can be modeled by the function
[tex]y=A\cos(\omega x)[/tex]
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:
[tex]\frac{\pi}{2}\omega =2\pi[/tex]
Thus:
[tex]\omega = 4[/tex]
Therefore, the equation of the sinusoid is:
[tex]y=3\cos (4x)[/tex]
Answer: C
