Let
C1,C2,C3 be the columns of
A and
R1,R2,R3 be the rows of
A.
From the given equations, we have:
A001=C3=131A101=C1+C3=344⇒C1=213Similarly, for the transpose
AT, the columns correspond to the rows of
A:
AT001=R3T=311⇒R3=[311]AT101=R1T+R3T=522⇒R1T=211⇒R1=[211]Using the elements of
C1,C3,R1, and
R3, we can construct the matrix
A with an unknown central element
b:
A=2131b1131We are given that
det(A)=1. Expanding along the first row:
det(A)=2(b−3)−1(1−9)+1(1−3b)=12b−6+8+1−3b=13−b=1⇒b=2Thus, the matrix
A is:
A=213121131We need to find
det(adj(A2+A)). Using the properties of determinants and adjoints:
det(adj(A2+A))=(det(A2+A))2=(det(A)⋅det(A+I))2First, find
A+I:
A+I=313131132Now, calculate
det(A+I):
det(A+I)=3(6−3)−1(2−9)+1(1−9)det(A+I)=3(3)−1(−7)+1(−8)=9+7−8=8Since
det(A)=1, we have:
det(A2+A)=1×8=8Finally, for a
3×3 matrix:
det(adj(A2+A))=83−1=82=64Answer:
64