Answer: Â (a) Amplitude = 19
         (b) Vertical Shift = 59
         (c) Period = 24        Â
         [tex]\bold{(d)\quad y=19\cos\bigg(\dfrac{\pi}{12}x\bigg)+59}[/tex]
         (e) The model = 50°,  the actual value = 52°
Step-by-step explanation:
The equation of a cosine function is: y = A cos (Bx - C) + D Â where
- Amplitude (A) is the distance from the center to the maximum
- Period (P) = 2Ï€/B Â --> B = 2Ï€/P
- Phase Shift = C/B
- Center (D) is the vertical shift
(a) Amplitude (A) = (Max - Min)/2
              = (77 - 40)/2
              = 37/2
              = 18.5  (I rounded it up to 19)
(b) Vertical Shift (aka Center) (D)= (Max + Min)/2
                           = (77 + 40)/2
                           = 117/2
                           = 58.5  (I rounded it up to 59)
(c) Period (P) = 24
  B = 2π/P
    = 2π/24
    = π/12
(d) There is no Phase Shift because the max is on the y-axis.
   A = 19, B = π/12, C = 0, D = 59
      ⇒ y = 19 cos(π/12)x + 59
(e) let x = -2 Â Â (-2 represents 10 am on the graph) Â Â Â
  ⇒  y = 19 cos(π/12)(-2) + 59
       = 19 cos (-π/6) + 59
       = 19(-1/2) + 59
       = -9.5 + 59
       = 49.5
The model estimates the temperature at 10 am to be ≈ 50°
The actual temperature from the table is 52°