Math Problem Statement

Selesaikan soal tersebut

Diketahui w_1, w_2, w_3, w_4, w_5, w_6, w_7, w_8 merupakan akar-akar dari persamaan: w^8 + 1 / (1 - 4√5) + 1 / (1 + 4√5) + (-1 - √5) / 2 = 0. Jika jumlah dari akar-akarnya adalah v, maka nilai dari v^2 adalah . .

Solution

We are given the equation:

w8+1145+11+45+152=0w^8 + \frac{1}{1 - 4\sqrt{5}} + \frac{1}{1 + 4\sqrt{5}} + \frac{-1 - \sqrt{5}}{2} = 0

The problem asks for the sum of the roots of this equation, denoted by vv, and the value of v2v^2.

Step 1: Analyze the equation

The roots of the equation w1,w2,,w8w_1, w_2, \ldots, w_8 are provided as solutions to this polynomial equation. However, we first simplify the constants on the right-hand side of the equation.

Simplify each term:

  1. Second term: 1145\frac{1}{1 - 4\sqrt{5}}
  2. Third term: 11+45\frac{1}{1 + 4\sqrt{5}}

We can sum these two terms:

1145+11+45=(1+45)+(145)(145)(1+45)\frac{1}{1 - 4\sqrt{5}} + \frac{1}{1 + 4\sqrt{5}} = \frac{(1 + 4\sqrt{5}) + (1 - 4\sqrt{5})}{(1 - 4\sqrt{5})(1 + 4\sqrt{5})} =1+45+14512(45)2=2180=279= \frac{1 + 4\sqrt{5} + 1 - 4\sqrt{5}}{1^2 - (4\sqrt{5})^2} = \frac{2}{1 - 80} = \frac{2}{-79}

Thus, these two terms simplify to 279\frac{-2}{79}.

Fourth term:

152\frac{-1 - \sqrt{5}}{2}

Step 2: Substituting into the equation

Now substitute the simplified values back into the original equation:

w8+279+152=0w^8 + \frac{-2}{79} + \frac{-1 - \sqrt{5}}{2} = 0

The equation becomes:

w8=279+1+52w^8 = \frac{2}{79} + \frac{1 + \sqrt{5}}{2}

Step 3: Sum of roots

The problem states that w1,w2,,w8w_1, w_2, \ldots, w_8 are the roots of this equation. For an 8th-degree polynomial of the form w8+=0w^8 + \ldots = 0, the sum of the roots (by Vieta’s formulas) is zero.

Thus, v=0v = 0, and v2=02=0v^2 = 0^2 = 0.

Final Answer:

The correct answer is:

0\boxed{0}

Would you like further clarification or details on any part of this solution?


Here are 5 related questions to expand your understanding:

  1. What are Vieta’s formulas, and how do they apply to polynomial equations?
  2. How can you simplify expressions involving square roots and radicals?
  3. What is the general approach to solving 8th-degree polynomial equations?
  4. How does the discriminant of a polynomial affect its number of real roots?
  5. What methods can be used to find the roots of higher-degree polynomials?

Tip: Vieta’s formulas are useful for quickly finding relationships between the coefficients of polynomials and their roots without needing to fully solve the equation.

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Math Problem Analysis

Mathematical Concepts

Polynomial Equations
Algebra
Root Summation

Formulas

Vieta's Formulas
Sum of Roots for a Polynomial Equation

Theorems

Vieta's Theorem

Suitable Grade Level

Grades 11-12