KCET2018MathematicsDeterminants
If ( x, y, z R ), then the value of determinant [ | array lll (5^ x +5^ -x )² & (5^ x -5^ -x )² & 1 (6^ x +6^ -x )² & (6^ x -6^ -x )² & 1 (7^ x +7^ -x )² & (7^ x -7^ -x )² & 1 array | is ]
Options
- A( 10 )
- B( 12 )
- C( 11 )
- D( 00 )
Correct answer
D. ( 00 )
Step-by-step solution
Given that, ( | array ccc (5^ x +5^ -x )² & (5^ x -5^ -x )² & 1 (6^ x +6^ -x )² & (6^ x -6^ -x )² & 1 (7^ x +7^ -x )² & (7^ x -7^ -x )² & 1 array | ) ( C₁ C₁-C₂ ) ( | array ccc 4 & (5^ x -5^ -x )² & 1 4 & (6^ x -6^ -x )² & 1 4 & (7^ x -7^ -x )² & 1 array |=4 | array ccc 1 & (5^ x -5^ -x )² & 1 1 & (6^ x -6^ -x )² & 1 1 & (7^ x -7^ -x )² & 1 array |=0 )