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COMEDK · Maths · 21. Matrices

If \(A=\left[\begin{array}{cc}2 & -3 \\ 5 & -7\end{array}\right]\), then \(A+A^{-1}=\)

  1. A \(\left[\begin{array}{ll}1 & 0 \\ 0 & 1\end{array}\right]\)
  2. B \(\left[\begin{array}{cc}-5 & 0 \\ 0 & -5\end{array}\right]\)
  3. C \(\left[\begin{array}{ll}5 & 0 \\ 0 & 5\end{array}\right]\)
  4. D \(\left[\begin{array}{cc}4 & 0 \\ 0 & -5\end{array}\right]\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(\left[\begin{array}{cc}-5 & 0 \\ 0 & -5\end{array}\right]\)

Step-by-step Solution

Detailed explanation

\(\quad A=\left[\begin{array}{cc}2 & -3 \\ 5 & -7\end{array}\right]\) \(\therefore \quad|A|=-14+15=1 \neq 0\) So, \(A^{-1}\) exists.…