Math Problem Statement

Find the value of k that makes the function continuous: f(x) = {kx^2, x ≥ -2; kx + 18, x < -2}.

Solution

To find the value of kk that makes the given piecewise function continuous, we need to ensure that the function is continuous at the point where the two pieces of the function meet, which is at x=2x = -2.

The function is given by:

\begin{cases} kx^2 & \text{if } x \geq -2 \\ kx + 18 & \text{if } x < -2 \end{cases}$$ ### Steps to ensure continuity at $$x = -2$$: 1. **For continuity**, the left-hand limit and the right-hand limit at $$x = -2$$ must be equal to the function's value at $$x = -2$$. 2. **Right-hand limit**: This is from the part of the function $$f(x) = kx^2$$ for $$x \geq -2$$. Substituting $$x = -2$$: $$f(-2) = k(-2)^2 = 4k$$ 3. **Left-hand limit**: This is from the part of the function $$f(x) = kx + 18$$ for $$x < -2$$. Substituting $$x = -2$$: $$f(-2) = k(-2) + 18 = -2k + 18$$ 4. **Set the right-hand limit equal to the left-hand limit** to ensure continuity: $$4k = -2k + 18$$ 5. **Solve for $$k$$**: $$4k + 2k = 18$$ $$6k = 18$$ $$k = 3$$ Thus, the value of $$k$$ that makes the function continuous is $$\boxed{3}$$. Would you like a more detailed explanation or have any other questions? Here are some related questions: 1. What happens to the graph of a function at points of discontinuity? 2. How do you determine if a piecewise function is differentiable? 3. Can a function be continuous but not differentiable at a point? 4. How do left-hand and right-hand limits help in proving continuity? 5. What is the difference between removable and non-removable discontinuities? **Tip**: Always remember that continuity at a point means the function's value and its limits from both directions must match at that point.

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Math Problem Analysis

Mathematical Concepts

Continuity
Piecewise Functions
Limits

Formulas

Right-hand limit = Left-hand limit
kx^2 for x ≥ -2
kx + 18 for x < -2

Theorems

Continuity Theorem
Limit Theorem

Suitable Grade Level

Grades 10-12