Chapter 4 Class 12 Determinants
Concept wise

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Ex 4.5, 1 (Method 1) Find adjoint of each of the matrices. [β 8(1&2@3&4)] A = [β 8(1&2@3&4)] adj A = [β 8(1&2@3&4)] = [β 8(π&βπ@βπ&π)] Ex 4.5, 1 (Method 2) Find adjoint of each of the matrices. [β 8(1&2@3&4)] Let A = [β 8(1&2@3&4)] adj A =[β 8(π΄11&π΄21@π΄12&π΄22)] Step 1: Calculate minors M11 = |β 8(2&2@3&4)| M12 = |β 8(2&2@3&4)| M21 = |β 8(1&2@3&4)| M22 = |β 8(1&2@3&4)|Step 2: Calculate cofactors A11 = γ"( β 1)" γ^(1+1) . M11 = γ"( β 1)" γ^2 4 = 4 A12 = γ"( β 1)" γ^(1+2) . M12 = γ"( β 1)" γ^3 (3) = ( β 1) (3) = β3 A21 = γ"( β 1)" γ^(2+1) . M21 = γ"( β 1)" γ^3 2 = ( β 1) (2) = β2 A22 = γ"( β 1)" γ^(2+2) (1) = γ"( β 1)" γ^4 (1) = 1 Step 3: Calculate adjoint adj A = [β 8(A11&A12@A21&A22)] = [β 8(π&βπ@βπ&π)]