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GUJCET · Maths · Determinants

If \(x, y \in R\) and \(\left|\begin{array}{lll}\left(a^x+a^{-x}\right)^2 & \left(a^x-a^{-x}\right)^2 & 1 \\ \left(b^x+b^{-x}\right)^2 & \left(b^x-b^{-x}\right)^2 & 1 \\ \left(c^x+c^{-x}\right)^2 & \left(c^x-c^{-x}\right)^2 & 1\end{array}\right|\) \(=2 y+6\) then, \(y=\) _________

  1. A \(-3\)
  2. B \(0\)
  3. C 3
  4. D 6
Verified Solution

Answer & Solution

Correct Answer

(A) \(-3\)

Step-by-step Solution

Detailed explanation

\(C_1 \to C_1 - C_2\) \(\left|\begin{array}{lll}\left(a^x+a^{-x}\right)^2 - \left(a^x-a^{-x}\right)^2 & \left(a^x-a^{-x}\right)^2 & 1 \\ \left(b^x+b^{-x}\right)^2 - \left(b^x-b^{-x}\right)^2 & \left(b^x-b^{-x}\right)^2 & 1 \\ \left(c^x+c^{-x}\right)^2 - \left(c^x-c^{-x}\right)^2 & \left(c^x-c^{-x}\right)^2 & 1\end{array}\right| = 2y+6\)