1.

Let A be a `2xx2`matrix with non-zero entriesand let `A^2=""I`, where I is `2xx2`identity matrix. Define Tr(A) =sum of diagonal elements of A and |A| = determinant of matrix A.Statement-1:`T r(A)""=""0`Statement-2:`|A|""=""1`(1)Statement-1 istrue, Statement-2 is true; Statement-2 is not the correct explanation forStatement-1(2)Statement-1 istrue, Statement-2 is false(3)Statement-1 isfalse, Statement-2 is true(4)Statement-1 istrue, Statement-2 is true; Statement-2 is the correct explanation forStatement-1

Answer» `A= [(a,b),(c,d)]`
`A^2 = [(a,b),(c,d)][(a,b),(c,d)] = [ (a^2 + bc,ab+bd),(ac+cd, bc+d^2)]= I`
`I= [(1,0),(0,1)]`
now,`a^2 + bc = bc+d^2 = 1`
`ab + bd = ac + cd = 0`
`b(a+d) = c(a+d) = 0`
`a+d = 0`
1)`T_r = (A) = a+d = 0`
2) `det(A) = ad*bc = a(-a) - bc= -a^2 - bc`
`= -(a^2 +bc)`
option 2 is correct


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