Linear Function D3F64C
1. **Stating the problem:** We analyze the function $f_1: y = x - 3$.
2. **Domain and range:** The function $y = x - 3$ is a linear function defined for all real numbers, so the domain is $\mathbb{R}$.
The range is also $\mathbb{R}$ because as $x$ takes any real value, $y$ can take any real value.
3. **Intercepts:**
- To find the $x$-intercept, set $y=0$:
$$0 = x - 3 \implies x = 3$$
So the $x$-intercept is at $(3,0)$.
- To find the $y$-intercept, set $x=0$:
$$y = 0 - 3 = -3$$
So the $y$-intercept is at $(0,-3)$.
4. **Monotonicity:** The function is linear with slope $1 > 0$, so it is strictly increasing (monotonically increasing) on $\mathbb{R}$.
5. **Extrema:** Since the function is strictly increasing and linear, it has no local maxima or minima.
6. **Boundedness:** The function is unbounded above and below.
7. **Parity:** Check if $f(-x) = f(x)$ or $f(-x) = -f(x)$:
$$f(-x) = -x - 3 \neq f(x) = x - 3$$
$$f(-x) = -x - 3 \neq -(x - 3) = -x + 3$$
So the function is neither even nor odd.
8. **Injectivity and invertibility:** The function is strictly increasing and thus injective, so it has an inverse.
9. **Finding the inverse function:**
Start with
$$y = x - 3$$
Swap $x$ and $y$:
$$x = y - 3$$
Solve for $y$:
$$y = x + 3$$
So the inverse function is:
$$f_1^{-1}(x) = x + 3$$
10. **Domain and range of inverse:**
Since the original function has domain $\mathbb{R}$ and range $\mathbb{R}$, the inverse also has domain $\mathbb{R}$ and range $\mathbb{R}$.
11. **Intercepts of inverse:**
- $x$-intercept: set $y=0$:
$$0 = x + 3 \implies x = -3$$
- $y$-intercept: set $x=0$:
$$y = 0 + 3 = 3$$
So the inverse intercepts are $(-3,0)$ and $(0,3)$.
12. **Intersection of $f$ and $f^{-1}$:**
Solve $f(x) = f^{-1}(x)$:
$$x - 3 = x + 3$$
This is never true, so no intersection points.
However, the function and its inverse always intersect on the line $y=x$.
Find points where $f(x) = x$:
$$x - 3 = x \implies -3 = 0$$
No solution.
Find points where $f^{-1}(x) = x$:
$$x + 3 = x \implies 3 = 0$$
No solution.
But the function and its inverse are reflections about $y=x$.
**Final answer:**
- Domain: $\mathbb{R}$
- Range: $\mathbb{R}$
- $x$-intercept: $(3,0)$
- $y$-intercept: $(0,-3)$
- Monotonically increasing
- No extrema
- Unbounded
- Neither even nor odd
- Inverse function: $f_1^{-1}(x) = x + 3$
- Inverse domain and range: $\mathbb{R}$
- Inverse intercepts: $(-3,0)$ and $(0,3)$
- No intersection points of $f$ and $f^{-1}$ except reflection symmetry about $y=x$.