Let M be an 4×4 matrix with real entries such that Mk=0, for some k≥1. Find the determinant value of (I+M), where, I be the 4 x 4 identity matrix.

Correct Answer: 1
By cayley hamilton theorem, M4 = 0. So, characteristic equation should be λ*4=0 and after solving we get 0 for every eigen value. Eigen values of (I+M) = Individual Eigen value of 1+m. So all the eigen values of (I+M) are 1 and Det(I+A) = 1.