Function Analyses
1. **Problem a:** Find the domain, intercepts, range, and asymptotes of $$f(x)=\frac{2x-1}{x^2-4}$$ and sketch its graph.
2. **Domain:** The denominator cannot be zero.
$$x^2-4=0 \implies x^2=4 \implies x=\pm 2$$.
Thus, domain is all real numbers except $$x=2$$ and $$x=-2$$.
3. **Intercepts:**
- **x-intercept:** Set numerator equal to zero.
$$2x-1=0 \implies x=\frac{1}{2}$$.
So, x-intercept: $$(\frac{1}{2}, 0)$$.
- **y-intercept:** Set $$x=0$$.
$$f(0)=\frac{2\cdot0 -1}{0-4}=\frac{-1}{-4}=\frac{1}{4}$$.
So, y-intercept is $$(0, \frac{1}{4})$$.
4. **Asymptotes:**
- **Vertical asymptotes:** Values where denominator is zero and numerator is nonzero.
At $$x=2$$ and $$x=-2$$, vertical asymptotes occur.
- **Horizontal asymptote:** Degree numerator is 1, denominator degree 2.
Horizontal asymptote is $$y=0$$.
5. **Range:** Since horizontal asymptote is $$y=0$$ and vertical asymptotes at $$x=\pm 2$$, the function takes all real values except possibly $$y=0$$.
Exact analysis shows range: all real $$y$$ except possibly $$0$$.
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6. **Problem b:** For $$f(x)=\frac{1}{2}x + 20$$, a linear function.
- Domain: all real numbers.
- Intercepts:
Set $$f(x)=0$$ for x-intercept:
$$0=\frac{1}{2}x+20 \implies x=-40$$
x-intercept: $$(-40,0)$$.
y-intercept: $$f(0)=20$$.
y-intercept: $$(0,20)$$.
- No asymptotes.
- Range: all real numbers.
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7. **Problem c:** $$f(x)=\frac{2x}{6} - 5 = \frac{x}{3} - 5$$.
- Domain: all real numbers.
- Intercepts:
x-intercept:
$$0=\frac{x}{3} - 5 \implies x=15$$
So, $$(15,0)$$.
y-intercept:
$$f(0) = -5$$
So, $$(0,-5)$$.
- No asymptotes.
- Range: all real numbers.
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