Even Function B3Cfa6
1. **Problem Statement:** Define even and odd functions, then find the domain and range of the function $f(x) = 1 + x^2$.
2. **Definitions:**
- An **even function** satisfies $f(-x) = f(x)$ for all $x$ in its domain.
- An **odd function** satisfies $f(-x) = -f(x)$ for all $x$ in its domain.
3. **Check if $f(x) = 1 + x^2$ is even or odd:**
Calculate $f(-x) = 1 + (-x)^2 = 1 + x^2 = f(x)$.
Since $f(-x) = f(x)$, $f$ is an **even function**.
4. **Find the domain:**
The function $f(x) = 1 + x^2$ is defined for all real numbers because $x^2$ is defined for all real $x$.
So, domain is $(-\infty, \infty)$.
5. **Find the range:**
Since $x^2 \geq 0$ for all real $x$, the minimum value of $f(x)$ is at $x=0$:
$$f(0) = 1 + 0 = 1$$
As $x^2$ increases without bound, $f(x)$ increases without bound.
Thus, range is $[1, \infty)$.
**Final answer:**
- $f(x) = 1 + x^2$ is an **even function**.
- Domain: $(-\infty, \infty)$.
- Range: $[1, \infty)$.