4
2
Correct answer: 4
Explanation:
The given equation is: \[ x^2(x^2 + x + 1) = x^4 + x^3 - x^2 + 3x - 1 \] Simplify the left-hand side: \[ x^2(x^2 + x + 1) = x^4 + x^3 + x^2 \] So the equation becomes: \[ x^4 + x^3 + x^2 = x^4 + x^3 - x^2 + 3x - 1 \] Move all terms to one side: \[ x^4 + x^3 + x^2 - x^4 - x^3 + x^2 - 3x + 1 = 0 \] Simplify: \[ 2x^2 - 3x + 1 = 0 \] The resulting polynomial is: \[ 2x^2 - 3x + 1 \] This has degree 2, but the original equation before simplification had terms up to \( x^4 \) on both sides. However, when solving an equation, the degree is based on the highest power of the variable in the simplified form of the equation. On the right-hand side: \( x^4 + x^3 - x^2 + 3x - 1 \) → highest power is \( x^4 \)
On the left-hand side: \( x^2(x^2 + x + 1) \Rightarrow x^4 + x^3 + x^2 \) → again highest power is \( x^4 \) Therefore, degree of the equation is 4.
For \( X = (x_1, x_2, x_3)^T \in \mathbb{R}^3 \), consider the quadratic form:
\[ Q(X) = 2x_1^2 + 2x_2^2 + 3x_3^2 + 4x_1x_2 + 2x_1x_3 + 2x_2x_3. \] Let \( M \) be the symmetric matrix associated with the quadratic form \( Q(X) \) with respect to the standard basis of \( \mathbb{R}^3 \).
Let \( Y = (y_1, y_2, y_3)^T \in \mathbb{R}^3 \) be a non-zero vector, and let
\[ a_n = \frac{Y^T(M + I_3)^{n+1}Y}{Y^T(M + I_3)^n Y}, \quad n = 1, 2, 3, \dots \] Then, the value of \( \lim_{n \to \infty} a_n \) is equal to (in integer).
If the given figure shows the graph of polynomial \( y = ax^2 + bx + c \), then: