Math Problem Statement

Given f(x) = (x^2 - 1) / (x^2 + 3x - 4), where is f(x) discontinuous? Classify the type of discontinuity.

Solution

The function given in the image is:

f(x)=x21x2+3x4f(x) = \frac{x^2 - 1}{x^2 + 3x - 4}

Part (a) - Where is f(x)f(x) discontinuous?

To find where f(x)f(x) is discontinuous, we need to examine the denominator x2+3x4x^2 + 3x - 4. Discontinuities occur when the denominator equals zero because division by zero is undefined.

So, let's solve:

x2+3x4=0x^2 + 3x - 4 = 0

Factoring the quadratic:

(x+4)(x1)=0(x + 4)(x - 1) = 0

This gives us the critical points x=4x = -4 and x=1x = 1, where f(x)f(x) is potentially discontinuous.

Part (b) - Classify the type of discontinuity

To classify the discontinuity, we must check the behavior of the function around these points.

1. At x=1x = 1:

The numerator is x21=(x1)(x+1)x^2 - 1 = (x - 1)(x + 1), so at x=1x = 1, the numerator also becomes zero. This creates a removable discontinuity at x=1x = 1 because the common factor (x1)(x - 1) cancels out.

After canceling the common factor, the function simplifies to:

f(x)=x+1x+4forx1f(x) = \frac{x + 1}{x + 4} \quad \text{for} \, x \neq 1

Thus, the discontinuity at x=1x = 1 is removable.

2. At x=4x = -4:

At x=4x = -4, the denominator becomes zero, but the numerator does not. This causes a non-removable (infinite) discontinuity, also known as a vertical asymptote, at x=4x = -4.

Conclusion:

  • f(x)f(x) is discontinuous at x=1x = 1 (removable discontinuity).
  • f(x)f(x) has an infinite discontinuity (vertical asymptote) at x=4x = -4.

Would you like more details on any of the steps? Here are some related questions:

  1. How do we determine the limit of a function around a removable discontinuity?
  2. What is the difference between removable and non-removable discontinuities?
  3. How can you factor more complex polynomials to find discontinuities?
  4. How does the behavior near a vertical asymptote affect the function graph?
  5. What happens to the simplified function x+1x+4\frac{x+1}{x+4} as x4x \to -4?

Tip: When checking for discontinuities, always verify whether the numerator and denominator share a common factor to identify removable discontinuities.

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Math Problem Analysis

Mathematical Concepts

Algebra
Rational Functions
Discontinuities
Factoring Quadratics

Formulas

Quadratic equation: ax^2 + bx + c = 0
Factoring quadratic: (x + a)(x + b)
Function simplification

Theorems

Removable Discontinuity
Non-removable (Infinite) Discontinuity

Suitable Grade Level

Grades 10-12