Unique solution

Definition

A unique solution refers to a situation where a system of equations has exactly one set of values that satisfies all the equations simultaneously. This concept is crucial as it indicates that the relationships between the variables are well-defined and that no other values can yield a true statement for the equations involved. Unique solutions arise under specific conditions related to the structure of the coefficients in the system, particularly when considering the rank of matrices and the consistency of equations.

5 Must Know Facts For Your Next Test

1. For a system of linear equations to have a unique solution, the number of equations must equal the number of unknowns and the determinant of the coefficient matrix must be non-zero.
2. In cases where a matrix is singular (determinant equals zero), the system may have no solutions or infinitely many solutions, but not a unique one.
3. When using Cramer's Rule, if the determinant is non-zero, it guarantees a unique solution for the system of linear equations.
4. Graphically, a unique solution corresponds to two lines intersecting at exactly one point in a two-dimensional space.
5. The concept of unique solutions is fundamental in applications such as optimization problems and modeling real-world scenarios in economics, engineering, and science.

Review Questions

• What conditions must be met for a system of linear equations to have a unique solution?
  • For a system of linear equations to have a unique solution, it must satisfy specific conditions: the number of independent equations must match the number of variables involved, and the determinant of the coefficient matrix must be non-zero. This ensures that the system is consistent and that there are no redundant or conflicting equations present.
• How does Gaussian elimination help in determining if a system has a unique solution?
  • Gaussian elimination transforms a system of linear equations into row-echelon form, which makes it easier to analyze the solutions. By examining the resulting rows, you can determine if there are leading entries in every row corresponding to each variable. If all variables have leading entries and there are no contradictory statements (like 0 = 1), then it confirms that the system has a unique solution.
• Evaluate how Cramer's Rule can be applied to find a unique solution and what its limitations are.
  • Cramer's Rule provides a direct way to find a unique solution for systems of linear equations with an equal number of equations and unknowns, given that the determinant of the coefficient matrix is non-zero. However, its limitations include being computationally intensive for large systems and not being applicable when the determinant is zero, which indicates either no solution or infinitely many solutions. This makes it less practical for larger matrices where other methods may be more efficient.

Related terms

Consistent System: A system of equations that has at least one solution, which can either be unique or infinite.

Matrix Rank: The maximum number of linearly independent row or column vectors in a matrix, indicating the dimension of the vector space spanned by its rows or columns.

Gaussian Elimination: A method used to solve systems of linear equations by transforming them into row-echelon form, making it easier to identify solutions.