

MCQOPTIONS
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1. |
If \(A=\left[ \begin{matrix}{{e}^{t}} & {{e}^{-t}}\text{cos }\!\!~\!\!\text{ }t & {{e}^{-t}}\text{sin }\!\!~\!\!\text{ }t \\{{e}^{t}} & -{{e}^{-t}}\text{cos }\!\!~\!\!\text{ }t-{{e}^{-t}}\text{sin }\!\!~\!\!\text{ }t & -{{e}^{-t}}\text{sin }\!\!~\!\!\text{ }t+{{e}^{-t}}\text{cos }\!\!~\!\!\text{ }t \\{{e}^{t}} & 2{{e}^{-t}}\text{sin }\!\!~\!\!\text{ }t & -2{{e}^{-t}}\text{cos }\!\!~\!\!\text{ }t \\\end{matrix} \right]\) then A is: |
A. | Invertible for all t ∈ R |
B. | Invertible only if t = π |
C. | Not invertible for any t ∈ R |
D. | Invertible only if \(\text{t}=\frac{\pi }{2}\) |
Answer» B. Invertible only if t = π | |