The common errors on Assign 3 are as follows:

1. Most of the students made a mistake in question 2.2.2, they should check the solutions. For a vector \alpha, (alpha)^2 has no meaning; (\alpha^T \alpha) is a scalar, and (\alpha \alpha^T) is an n*n matrix.
2. Some students made a mistake in question 4.1.2. Newton's step is different for minimizing a function and finding a root.