Math Problem Statement

If f(x) = 2 + |x - 3| for all x, then the value of the derivative f'(x) at x = 3 is:

Solution

The given function is f(x)=2+x3f(x) = 2 + |x - 3|, and you are asked to find the value of the derivative f(x)f'(x) at x=3x = 3.

Key points:

  • The absolute value function x3|x - 3| introduces a potential non-differentiability at x=3x = 3.
  • We will first check if the function is differentiable at x=3x = 3.

Step-by-Step Analysis:

  1. Piecewise Definition of the Function: The function can be written as:

    x - 3 & \text{if } x \geq 3 \\ 3 - x & \text{if } x < 3 \end{cases}$$
  2. Derivative on Either Side of x=3x = 3:

    • For x>3x > 3, f(x)=2+(x3)=x1f(x) = 2 + (x - 3) = x - 1, and its derivative is f(x)=1f'(x) = 1.
    • For x<3x < 3, f(x)=2+(3x)=5xf(x) = 2 + (3 - x) = 5 - x, and its derivative is f(x)=1f'(x) = -1.
  3. At x=3x = 3:

    • As we approach from the right (x3+x \to 3^+), f(x)=1f'(x) = 1.
    • As we approach from the left (x3x \to 3^-), f(x)=1f'(x) = -1.
    • Since the left-hand and right-hand derivatives are not equal, the function is not differentiable at x=3x = 3.

Conclusion:

The derivative does not exist at x=3x = 3.

The correct answer is (E) Nonexistent.

Would you like further explanation on any of the steps?

Here are five related questions:

  1. What does it mean for a function to be differentiable at a point?
  2. How do you compute the derivative of an absolute value function?
  3. What is the significance of the left-hand and right-hand derivatives in determining differentiability?
  4. How do piecewise functions affect differentiability and continuity?
  5. Can you provide more examples of functions that are not differentiable at a point?

Tip: Always check both continuity and the equality of the left-hand and right-hand derivatives when dealing with absolute value functions at critical points.

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Math Problem Analysis

Mathematical Concepts

Calculus
Differentiation
Absolute Value Function
Piecewise Functions

Formulas

f'(x) = lim (h -> 0) (f(x + h) - f(x)) / h

Theorems

Non-Differentiability at a Sharp Corner
Left-hand and Right-hand Derivatives

Suitable Grade Level

Grades 11-12, College Level