Trig Functions
1. **Problem statement:**
Sketch the functions $f(x) = 2\sin x$ and $g(x) = \sin x + 1$ for $x \in (0^\circ, 360^\circ)$. Find the period of $f$ and the amplitude of $g$.
2. Given $f(x) = a \cos x$ and $g(x) = \sin x + q$, find $a$, $q$, the range of $g$, and solve $g(x) - f(x) = 2$.
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### Step 1: Sketching the functions
- $f(x) = 2\sin x$ is a sine wave with amplitude 2.
- $g(x) = \sin x + 1$ is a sine wave shifted up by 1.
### Step 2: Period of $f(x)$
- The period of $\sin x$ is $360^\circ$.
- Multiplying by 2 (amplitude) does not change the period.
- Therefore, period of $f(x)$ is $360^\circ$.
### Step 3: Amplitude of $g(x)$
- Amplitude is the coefficient of $\sin x$, which is 1.
- Vertical shift $+1$ does not affect amplitude.
- So amplitude of $g$ is 1.
### Step 4: Finding $a$ and $q$ from the graph
- $f(x) = a \cos x$ has amplitude $a$.
- From the graph, amplitude $a = 1$.
- $g(x) = \sin x + q$ is shifted up by $q$.
- From the graph, vertical shift $q = 1$.
### Step 5: Range of $g(x)$
- Since $\sin x$ ranges from $-1$ to $1$, adding $q=1$ shifts range to $0 \leq y \leq 2$.
### Step 6: Solve $g(x) - f(x) = 2$
- Substitute: $\sin x + 1 - a \cos x = 2$ with $a=1$.
- Simplify: $\sin x + 1 - \cos x = 2$.
- Rearrange: $\sin x - \cos x = 1$.
### Step 7: Solve $\sin x - \cos x = 1$
- Use identity: $\sin x - \cos x = \sqrt{2} \sin(x - 45^\circ)$.
- So $\sqrt{2} \sin(x - 45^\circ) = 1$.
- Divide both sides: $\sin(x - 45^\circ) = \frac{1}{\sqrt{2}} = \sin 45^\circ$.
- Solutions in $0^\circ < x < 360^\circ$:
- $x - 45^\circ = 45^\circ \Rightarrow x = 90^\circ$
- $x - 45^\circ = 180^\circ - 45^\circ = 135^\circ \Rightarrow x = 180^\circ$
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**Final answers:**
1.
- a) Sketch as described.
- b) Period of $f$ is $360^\circ$.
- c) Amplitude of $g$ is 1.
2.
- a) $a = 1$
- b) $q = 1$
- c) Range of $g$ is $0 \leq y \leq 2$
- d) $x = 90^\circ, 180^\circ$ satisfy $g(x) - f(x) = 2$.