Sine Function 50Ef5D
1. **Problem Statement:**
Find the period, amplitude, constants affecting the function, domain, and range of the sine function given in part 2a and graph the function in part 2b.
2. **Recall the sine function formula:**
The general form of a sine function is $$y = A \sin(Bx + C) + D$$ where:
- $A$ is the amplitude (height of the wave from the center line).
- $B$ affects the period of the function.
- $C$ is the phase shift (horizontal shift).
- $D$ is the vertical shift.
3. **Analyze the sine graph in 2a:**
- The standard sine function is $$y = \sin x$$.
- Amplitude $A = 1$ (since sine ranges from -1 to 1).
- Period $P = \frac{2\pi}{B} = 2\pi$ (since $B=1$ here).
- Domain: all real numbers $(-\infty, \infty)$.
- Range: $[-1, 1]$.
- Constants affecting the function: amplitude $1$, no vertical or horizontal shifts.
4. **Graph the function in 2b:**
Given $$y = \frac{4}{5} \sin\left(3x + \frac{7}{6}\pi\right) + 1$$
- Amplitude $A = \frac{4}{5}$.
- $B = 3$, so period $$P = \frac{2\pi}{3}$$.
- Phase shift $$= -\frac{C}{B} = -\frac{\frac{7}{6}\pi}{3} = -\frac{7\pi}{18}$$ (shift left).
- Vertical shift $D = 1$ (shift up by 1).
- Domain: all real numbers $(-\infty, \infty)$.
- Range: from $1 - \frac{4}{5} = \frac{1}{5}$ to $1 + \frac{4}{5} = \frac{9}{5}$.
5. **Desmos LaTeX for graph 2b:**
$$y=\frac{4}{5}\sin\left(3x + \frac{7}{6}\pi\right) + 1$$
6. **Relation between graphs 2a and 2b:**
- Graph 2b is a vertically shifted, horizontally compressed, and phase-shifted version of the standard sine wave in 2a.
- Amplitude decreased from 1 to $\frac{4}{5}$.
- Period decreased from $2\pi$ to $\frac{2\pi}{3}$.
- Shifted left by $\frac{7\pi}{18}$ and up by 1.
**Final answers:**
- 2a: Amplitude = 1, Period = $2\pi$, Domain = $(-\infty, \infty)$, Range = $[-1,1]$.
- 2b: Amplitude = $\frac{4}{5}$, Period = $\frac{2\pi}{3}$, Phase shift = $-\frac{7\pi}{18}$, Vertical shift = 1, Domain = $(-\infty, \infty)$, Range = $[\frac{1}{5}, \frac{9}{5}]$.