Continuity Value K E7771C
1. **State the problem:** Determine the value of $k$ such that the piecewise function
$$f(x) = \begin{cases} kx + 3, & x < 1 \\ 8 - x^2, & x \geq 1 \end{cases}$$
is continuous at $x = 1$.
2. **Recall the conditions for continuity at $x = a$:**
1. $f(a)$ is defined.
2. $\lim_{x \to a} f(x)$ exists.
3. $\lim_{x \to a} f(x) = f(a)$.
3. **Apply these conditions at $x = 1$:**
- Calculate $f(1)$ from the second piece since $x \geq 1$:
$$f(1) = 8 - 1^2 = 7$$
- Calculate the left-hand limit as $x \to 1^-$:
$$\lim_{x \to 1^-} f(x) = \lim_{x \to 1^-} (kx + 3) = k(1) + 3 = k + 3$$
- Calculate the right-hand limit as $x \to 1^+$:
$$\lim_{x \to 1^+} f(x) = \lim_{x \to 1^+} (8 - x^2) = 8 - 1 = 7$$
4. **Set the left-hand limit equal to $f(1)$ for continuity:**
$$k + 3 = 7$$
5. **Solve for $k$:**
$$k = 7 - 3 = 4$$
**Final answer:**
$$\boxed{4}$$