1. **State the problem:**
We are given several exponential functions and need to find for each:
i. The equation of the horizontal asymptote.
ii. The y-intercept.
Also, state the domain and range for given functions.
2. **Recall the general form and rules:**
An exponential function is generally of the form $$y = a b^x + q$$ where:
- $$a$$ is the vertical stretch/compression and reflection factor.
- $$b$$ is the base of the exponential (positive, not equal to 1).
- $$q$$ is the vertical shift.
**Horizontal asymptote:** The line $$y = q$$ is the horizontal asymptote.
**Y-intercept:** Set $$x=0$$, then $$y = a b^0 + q = a \cdot 1 + q = a + q$$.
**Domain:** For all exponential functions, domain is $$(-\infty, \infty)$$.
**Range:** Depends on $$a$$ and $$q$$:
- If $$a > 0$$, range is $$(q, \infty)$$.
- If $$a < 0$$, range is $$(-\infty, q)$$.
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3. **Find asymptotes and y-intercepts for given functions:**
**a) $$y = 2^x + 1$$**
- Asymptote: $$y = 1$$
- Y-intercept: $$y = 2^0 + 1 = 1 + 1 = 2$$
**b) $$y = 3(2)^x - 2$$**
- Asymptote: $$y = -2$$
- Y-intercept: $$y = 3 \cdot 2^0 - 2 = 3 - 2 = 1$$
**c) $$y = -2(2)^x + 3$$**
- Asymptote: $$y = 3$$
- Y-intercept: $$y = -2 \cdot 1 + 3 = 1$$
**e) $$y = 3^x - 1$$**
- Asymptote: $$y = -1$$
- Y-intercept: $$y = 1 - 1 = 0$$
**f) $$y = -3^x - 1$$**
- Asymptote: $$y = -1$$
- Y-intercept: $$y = -1 - 1 = -2$$
**g) $$f(x) = 2(3)^x + 1$$**
- Asymptote: $$y = 1$$
- Y-intercept: $$y = 2 \cdot 1 + 1 = 3$$
**i) $$y = -2(4)^x + 3$$**
- Asymptote: $$y = 3$$
- Y-intercept: $$y = -2 \cdot 1 + 3 = 1$$
**j) $$f(x) = 5^x$$**
- Asymptote: $$y = 0$$
- Y-intercept: $$y = 1$$
**k) $$y = 0.5(2)^x + 1$$**
- Asymptote: $$y = 1$$
- Y-intercept: $$y = 0.5 \cdot 1 + 1 = 1.5$$
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4. **Domain and range for given functions:**
**a) $$y = 4^x$$**
- Domain: $$(-\infty, \infty)$$
- Range: $$(0, \infty)$$ (since $$a=1>0$$ and $$q=0$$)
**b) $$y = 2^x - 3$$**
- Domain: $$(-\infty, \infty)$$
- Range: $$(-3, \infty)$$
**c) $$y = 3(\frac{1}{4})^x + 4$$**
- Domain: $$(-\infty, \infty)$$
- Range: $$(4, \infty)$$ (since $$a=3>0$$ and $$q=4$$)
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**Summary:**
- Horizontal asymptote is always $$y = q$$.
- Y-intercept is $$a + q$$.
- Domain is all real numbers.
- Range depends on sign of $$a$$ and vertical shift $$q$$.
This completes the solution for the first question about asymptotes, y-intercepts, domain, and range.
Exponential Functions 1F8243
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