Math Problem Statement

Solve the following mathematical problems: 1. Find the value of 'a' such that A(2) = 3 for the polynomial A(x) = 2x^3 - 3ax + 5. 2. Calculate the value of F(x) - G(x) at x = 2, where F(x) = x^2n - x^(2n-1) + ... + x^2 - x + 1 and G(x) = -x^(2n+1) + x^2n - x^(2n-1) + ... + x^2 - x + 1.

Solution

Let's analyze the mathematical problems presented in the image.

Câu 4:

Given the polynomial A(x)=2x33ax+5A(x) = 2x^3 - 3ax + 5 (where aa is a constant), find aa such that P(2)=3P(2) = 3.

First, we interpret this question as requiring us to substitute x=2x = 2 into the polynomial A(x)A(x) and set it equal to 3, then solve for aa.

A(2)=2(23)3a(2)+5=3A(2) = 2(2^3) - 3a(2) + 5 = 3 A(2)=2(8)6a+5=3A(2) = 2(8) - 6a + 5 = 3 166a+5=316 - 6a + 5 = 3 216a=321 - 6a = 3 6a=321-6a = 3 - 21 6a=18-6a = -18 a=3a = 3

So, the value of aa is 3.

Câu 5:

Given:

  • F(x)=x2nx2n1++x2x+1F(x) = x^{2n} - x^{2n-1} + \dots + x^2 - x + 1
  • G(x)=x2n+1+x2nx2n1++x2x+1G(x) = -x^{2n+1} + x^{2n} - x^{2n-1} + \dots + x^2 - x + 1

We are asked to calculate the value of F(x)G(x)F(x) - G(x) at x=2x = 2.

Let's first subtract G(x)G(x) from F(x)F(x): F(x)G(x)=(x2nx2n1++x2x+1)(x2n+1+x2nx2n1++x2x+1)F(x) - G(x) = \left( x^{2n} - x^{2n-1} + \dots + x^2 - x + 1 \right) - \left( -x^{2n+1} + x^{2n} - x^{2n-1} + \dots + x^2 - x + 1 \right) This simplifies to: F(x)G(x)=x2n+1F(x) - G(x) = x^{2n+1}

Now, substitute x=2x = 2: F(2)G(2)=22n+1F(2) - G(2) = 2^{2n+1}

Thus, the value of F(2)G(2)F(2) - G(2) is 22n+12^{2n+1}.


Let me know if you'd like further details or explanations.

Related Questions:

  1. Can you explain why the highest degree term dominates the subtraction in Câu 5?
  2. What happens if x=2x = -2 in the expression for F(x)G(x)F(x) - G(x)?
  3. How would you derive the general form of F(x)G(x)F(x) - G(x) for arbitrary xx?
  4. What is the significance of solving for aa in Câu 4 if A(x)A(x) had additional terms?
  5. How does changing the degree of the polynomial F(x)F(x) affect the behavior of the function as nn increases?

Tip:

When dealing with polynomials, always look for patterns or simplifications when subtracting similar functions!

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Math Problem Analysis

Mathematical Concepts

Polynomials
Algebraic Substitution
Polynomial Subtraction

Formulas

A(x) = 2x^3 - 3ax + 5
F(x) = x^2n - x^(2n-1) + ... + x^2 - x + 1
G(x) = -x^(2n+1) + x^2n - x^(2n-1) + ... + x^2 - x + 1

Theorems

Polynomial simplification
Algebraic equation solving

Suitable Grade Level

Grades 10-12