AP EAMCET202018 Sep 2020Morning ShiftMathematicsMatricesActual
If (A= [ array cc a+i b & c+i d -c+i d & a-i b array ] ) and (A⁻¹= [ array cc a+i b & -c-i d -c+i d & a-i b array ] ). Find ( (a^2+b^2+c^2+d^2 ) ).
Options
- A1
- B-1
- C(i )
- D(-i )
Correct answer
A. 1
Step-by-step solution
Given matrix (A= [ array cc a+i b & c+i d -c+i d & a-i b array ] ) So, ( A⁻¹= 1 |A| [ array cc a-i b & -c-i d c-i d & a+i b array ] ) ( aligned & = 1 a^2+b^2+c^2+d^2 [ array cc a-i b & -c-i d c-i d & a+i b array ] & = [ array cc a+i b & -c-i d -c+i d & a-i b array ] (given) aligned ) ( b=0 ) and (c=d=0 ) and (a^2+b^2+c^2+d^2=1 )