Explanation
[tex]y=Acos(Bx+C)+D[/tex]
Where A is the Amplitude =5
Also
[tex]\begin{gathered} period=\frac{2\pi}{B} \\ 4=\frac{2\pi}{B} \\ 4B=2\pi \\ B=\frac{2\pi}{4} \\ B=\frac{\pi}{2} \end{gathered}[/tex]
D represents the midline. While C is the phase shift that is not given, Therefore, the equation becomes;
[tex]\begin{gathered} y=5cos(\frac{\pi}{2}x+0)+3 \\ y=5cos(\frac{\pi}{2}x)+3 \end{gathered}[/tex]
Answer:
[tex]y=5cos(\frac{\pi}{2}x)+3[/tex]
