KCET · Maths · Matrices
Consider the following statements:
Statement I: If A is a non-singular matrix, then \(A^{-1}\) exists.
Statement II: If A and B are symmetric matrices of same order, then \((AB - BA)\) is a skew symmetric matrix.
Choose the correct option.
- A Statement I is true and Statement II is false
- B Statement I is false and Statement II is false
- C Statement I is true and Statement II is true
- D Statement I is false and Statement II is true
Answer & Solution
Correct Answer
(C) Statement I is true and Statement II is true
Step-by-step Solution
Detailed explanation
Statement I:
A non-singular matrix is a square matrix whose determinant is non-zero, i.e., \(|A| \neq 0\).
For any non-singular matrix, the inverse \(A^{-1}\) always exists and is given by \(A^{-1} = \dfrac{1}{|A|} \text{adj}(A)\).
Thus, Statement I is true.
Statement II:
Given \(A\) and \(B\) are symmetric matrices of the same order, we have \(A^T = A\) and \(B^T = B\).
Let \(P = AB - BA\).
Taking the transpose of \(P\):
\(P^T = (AB - BA)^T\)
\(P^T = (AB)^T - (BA)^T\)
\(P^T = B^T A^T - A^T B^T\)
Substituting \(A^T = A\) and \(B^T = B\):
\(P^T = BA - AB\)
\(P^T = -(AB - BA) = -P\)
Since \(P^T = -P\), the matrix \((AB - BA)\) is a skew-symmetric matrix.
Thus, Statement II is true.
Both Statement I and Statement II are true.
Answer: Statement I is true and Statement II is true
A non-singular matrix is a square matrix whose determinant is non-zero, i.e., \(|A| \neq 0\).
For any non-singular matrix, the inverse \(A^{-1}\) always exists and is given by \(A^{-1} = \dfrac{1}{|A|} \text{adj}(A)\).
Thus, Statement I is true.
Statement II:
Given \(A\) and \(B\) are symmetric matrices of the same order, we have \(A^T = A\) and \(B^T = B\).
Let \(P = AB - BA\).
Taking the transpose of \(P\):
\(P^T = (AB - BA)^T\)
\(P^T = (AB)^T - (BA)^T\)
\(P^T = B^T A^T - A^T B^T\)
Substituting \(A^T = A\) and \(B^T = B\):
\(P^T = BA - AB\)
\(P^T = -(AB - BA) = -P\)
Since \(P^T = -P\), the matrix \((AB - BA)\) is a skew-symmetric matrix.
Thus, Statement II is true.
Both Statement I and Statement II are true.
Answer: Statement I is true and Statement II is true
See the Complete Solution
Get step-by-step explanations for this and 2.5 Lakh+ more JEE, NEET & CET questions.
- Unlock all solutions
- Practice the full chapter
- Track accuracy across PYQs
4.8 rated on Google Play · 14,000+ reviews
More questions from Maths
- The number of solutions of the equation \(\mathrm{z}^{2}+\overline{\mathrm{z}}=0\), where \(\mathrm{z} \in \mathrm{C}\), areKCET 2012 Easy
- A man takes a step forward with probability \( 0.4 \) and one step backward with probability \( 0.6 \),
then the probability that at the end of eleven steps he is one step away from the starting point
isKCET 2015 Hard - \(\int_{0}^{1} x(1-x)^{3 / 2} d x\) isKCET 2010 Hard
- Which of the following is false ?KCET 2008 Medium
- The value of \(\int \frac{x^{2} d x}{\sqrt{x^{6}+a^{6}}}\) is equal toKCET 2021 Medium
- The length of the subtangent to the curve \(x^{2} y^{2}=a^{4}\) at \((-a, a)\) isKCET 2007 Hard
More PYQs from KCET
- Ribose sugar is present inKCET 2009 Medium
- In an alkaline medium, glycine predominantly exists as/in a/anKCET 2011 Easy
- The statement that is NOT correct isKCET 2014 Easy
- A thick metal wire of density \(\rho\) and length \(L\) is hung from a rigid support. The increase in length of the wire due to its own weight is ( \(Y=\) Young's modulus of the material of the wire)KCET 2024 Medium
- During chemiosmotic synthesis at ATP in photosynthesisKCET 2019 Medium
- \(10 \mathrm{~cm}^{3}\) of \(0.1 \mathrm{~N}\) monobasic acid requires \(15 \mathrm{~cm}^{3}\) of sodium hydroxide solution whose normality isKCET 2008 Medium