Math Problem Statement

Find all values of x for which the function is continuous. (Enter your answer in interval notation.) g(x) =

x under square root x3 − 3x2 − 10x

Solution

To determine where the function g(x)=x33x210xg(x) = \sqrt{x^3 - 3x^2 - 10x} is continuous, we need to ensure that the expression inside the square root is non-negative. This is because the square root of a negative number is not defined in the real number system.

Thus, we require: x33x210x0x^3 - 3x^2 - 10x \geq 0 Now, let’s factor the cubic expression: x33x210x=x(x23x10)x^3 - 3x^2 - 10x = x(x^2 - 3x - 10) Next, we factor x23x10x^2 - 3x - 10: x23x10=(x5)(x+2)x^2 - 3x - 10 = (x - 5)(x + 2) So, the function becomes: g(x)=x(x5)(x+2)g(x) = \sqrt{x(x - 5)(x + 2)} Now, we need to solve the inequality: x(x5)(x+2)0x(x - 5)(x + 2) \geq 0

Step 1: Find the critical points

The critical points occur where each factor equals zero:

  • x=0x = 0
  • x=5x = 5
  • x=2x = -2

Step 2: Test intervals

We will test the sign of x(x5)(x+2)x(x - 5)(x + 2) in the following intervals:

  1. (,2)(-\infty, -2)
  2. (2,0)(-2, 0)
  3. (0,5)(0, 5)
  4. (5,)(5, \infty)

We check the sign of the product in each of these intervals by picking test points within each interval:

  1. For x=3x = -3 in the interval (,2)(-\infty, -2): (3)(35)(3+2)=(3)(8)(1)=24(negative)(-3)(-3 - 5)(-3 + 2) = (-3)(-8)(-1) = -24 \quad \text{(negative)}

  2. For x=1x = -1 in the interval (2,0)(-2, 0): (1)(15)(1+2)=(1)(6)(1)=6(positive)(-1)(-1 - 5)(-1 + 2) = (-1)(-6)(1) = 6 \quad \text{(positive)}

  3. For x=1x = 1 in the interval (0,5)(0, 5): (1)(15)(1+2)=(1)(4)(3)=12(negative)(1)(1 - 5)(1 + 2) = (1)(-4)(3) = -12 \quad \text{(negative)}

  4. For x=6x = 6 in the interval (5,)(5, \infty): (6)(65)(6+2)=(6)(1)(8)=48(positive)(6)(6 - 5)(6 + 2) = (6)(1)(8) = 48 \quad \text{(positive)}

Step 3: Analyze the solution

The expression x(x5)(x+2)0x(x - 5)(x + 2) \geq 0 is satisfied when the product is positive or zero. From our sign test:

  • The product is non-negative in the intervals [2,0][-2, 0] and [5,)[5, \infty).
  • The product is zero at x=2,0,5x = -2, 0, 5.

Thus, the function g(x)g(x) is continuous for x[2,0][5,)x \in [-2, 0] \cup [5, \infty).

Final Answer:

The values of xx for which the function is continuous are: [2,0][5,)\boxed{[-2, 0] \cup [5, \infty)}

Would you like further details or have any other questions on this?

Here are some related questions for you to explore:

  1. How would the continuity change if the function was x33x2+10x\sqrt{x^3 - 3x^2 + 10x}?
  2. What is the domain of the function f(x)=x2+4x+3f(x) = \sqrt{x^2 + 4x + 3}?
  3. How do you find the points where a piecewise function is continuous?
  4. What is the difference between continuity and differentiability?
  5. Can a function be continuous at a point but not differentiable there?

Tip: Always check the domain restrictions for square roots—ensure the expression under the root is non-negative!

Ask a new question for Free

By Image

Drop file here or Click Here to upload

Math Problem Analysis

Mathematical Concepts

Continuity
Inequalities
Cubic Functions
Square Root Functions
Interval Notation

Formulas

x(x - 5)(x + 2) ≥ 0

Theorems

Intermediate Value Theorem
Sign Chart Method

Suitable Grade Level

Grades 11-12