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CUET · MATHS · PYQ PAPER 2025

The inverse of the matrix \(\left[\begin{array}{lll}4 & 0 & 0 \\ 0 & 5 & 0 \\ 0 & 0 & 6\end{array}\right]\) is

  1. A \(\left[\begin{array}{ccc}-\frac{1}{4} & 0 & 0 \\ 0 & -\frac{1}{5} & 0 \\ 0 & 0 & -\frac{1}{6}\end{array}\right]\)
  2. B \(\left[\begin{array}{ccc}-\frac{1}{30} & 0 & 0 \\ 0 & \frac{1}{24} & 0 \\ 0 & 0 & \frac{1}{20}\end{array}\right]\)
  3. C \(\left[\begin{array}{ccc}\frac{1}{4} & 0 & 0 \\ 0 & \frac{1}{5} & 0 \\ 0 & 0 & \frac{1}{6}\end{array}\right]\)
  4. D \(\left[\begin{array}{lll}6 & 0 & 0 \\ 0 & 5 & 0 \\ 0 & 0 & 4\end{array}\right]\)
Verified Solution

Answer & Solution

Correct Answer

(C) \(\left[\begin{array}{ccc}\frac{1}{4} & 0 & 0 \\ 0 & \frac{1}{5} & 0 \\ 0 & 0 & \frac{1}{6}\end{array}\right]\)

Step-by-step Solution

Detailed explanation

\( \left[\begin{array}{lll}4 & 0 & 0 \\ 0 & 5 & 0 \\ 0 & 0 & 6\end{array}\right]^{-1} = \left[\begin{array}{ccc}\frac{1}{4} & 0 & 0 \\ 0 & \frac{1}{5} & 0 \\ 0 & 0 & \frac{1}{6}\end{array}\right] \)