To solve the cubic equation \( x^3 - 4x^2 - x - 1 = 0 \), we can use methods such as the Rational Root Theorem, synthetic division, or numerical methods for more complex roots. Here's the step-by-step process:

### 1. **Check for Rational Roots:**
Using the Rational Root Theorem, the possible rational roots are the factors of the constant term (-1) divided by the factors of the leading coefficient (1). This gives us the possible rational roots: \( \pm 1 \).

### 2. **Test Possible Rational Roots:**
Let's test \( x = 1 \) and \( x = -1 \):

- For \( x = 1 \):
  \[
  1^3 - 4(1)^2 - 1 - 1 = 1 - 4 - 1 - 1 = -5 \quad (\text{not a root})
  \]
- For \( x = -1 \):
  \[
  (-1)^3 - 4(-1)^2 - (-1) - 1 = -1 - 4 + 1 - 1 = -5 \quad (\text{not a root})
  \]

Since neither \( x = 1 \) nor \( x = -1 \) is a root, there are no simple rational roots.

### 3. **Use Numerical Methods:**
Since this cubic equation doesn't have easily factorable roots, we can apply numerical methods like the **Newton-Raphson method** or use a calculator/software to find the roots approximately.

Using numerical methods or a calculator, the approximate roots are:

- \( x_1 \approx 4.13 \)
- \( x_2 \approx -0.58 \)
- \( x_3 \approx 0.45 \)

These roots can be found by more precise tools if needed, and their values can be further refined.

Would you like further details or have any questions? 

Here are some related questions to consider:

1. What are the general methods for solving cubic equations?
2. How does the Rational Root Theorem help in solving polynomial equations?
3. What is the Newton-Raphson method for finding roots of equations?
4. How can synthetic division be used to factor cubic equations?
5. What are the possible types of roots a cubic equation can have?

**Tip:** When solving cubic equations, checking for simple rational roots first can save a lot of time before resorting to numerical methods.

Learn how to solve the cubic equation x^3 - 4x^2 - x - 1 = 0 with a detailed step-by-step solution. This problem involves the Rational Root Theorem, testing for rational roots, and using numerical methods like the Newton-Raphson method to find approximate roots. Suitable for advanced high school students (Grades 10-12).

Math Problem Statement

Solution

Ask a new question for Free

By Image

Math Problem Analysis

Mathematical Concepts

Formulas

Theorems

Suitable Grade Level

Related Recommendation