Are (1, 2) and (2, 4) linearly independent?

💡 Is one a scalar multiple of the other?

For A = [[2, 0], [0, 3]], find an eigenvector with λ = 3.

💡 A diagonal matrix has standard basis as eigenvectors.

Trace of A = [[1, 2, 3], [4, 5, 6], [7, 8, 9]]:

💡 Trace = sum of diagonal entries.