Hence ∂ ∂ I 1 ∂ ∂ A λ λ 2 + ∂ ∂ I 2 ∂ ∂ A λ λ + ∂ ∂ I 3 ∂ ∂ A = det ( λ λ 1 + A ) [ ( λ λ 1 + A ) − − 1 ] T or, ( λ λ 1 + A ) T ⋅ ⋅ [ ∂ ∂ I 1 ∂ ∂ A λ λ 2 + ∂ ∂ I 2 ∂ ∂ A λ λ + ∂ ∂ I 3 ∂ ∂ A ] = det ( λ λ 1 + A ) 1 .