If A is an invertible square matrix of order 3 and |A| = 5, then find the value of |adj A|.
If the determinant of matrix A of order 3 × 3 is of value 4, write the value of |3A|.
If A and B are square matrices of order 3 such that |A| = –1, |B| = 3, then find the value of |2AB|.
If A is a square matrix such that A² = I, then find the simplified value of (A – I)³ + (A + I)³ – 7A.
Write the differential equation obtained by eliminating the arbitrary constant C in the equation representing the family of curves xy = C cos x.