Cosine Parameters
1. **Problem Statement:**
Determine the values of $a$, $b$, and $c$ in the function $f(x) = a \cos(bx) + c$ for $0^\circ \leq x \leq 360^\circ$, given the graph oscillates between $y=0.5$ and $y=1.5$ with three full cycles.
2. **Formula and Explanation:**
The general form is $f(x) = a \cos(bx) + c$ where:
- $a$ is the amplitude (half the distance between max and min values),
- $b$ affects the period (number of cycles in $360^\circ$),
- $c$ is the vertical shift (midline of the wave).
3. **Find $a$ (Amplitude):**
Amplitude $a = \frac{\text{max} - \text{min}}{2} = \frac{1.5 - 0.5}{2} = 0.5$
4. **Find $c$ (Vertical Shift):**
Vertical shift $c = \frac{\text{max} + \text{min}}{2} = \frac{1.5 + 0.5}{2} = 1$
5. **Find $b$ (Frequency):**
The period $T$ is the length of one full cycle. Since there are 3 full cycles in $360^\circ$,
$$T = \frac{360^\circ}{3} = 120^\circ$$
The relationship between $b$ and period $T$ is:
$$b = \frac{360^\circ}{T} = \frac{360^\circ}{120^\circ} = 3$$
6. **Final values:**
$$a = 0.5, \quad b = 3, \quad c = 1$$
These values match the graph's amplitude, frequency, and vertical shift exactly.