Talk:06-240/Homework Assignment 5

For the test, do we have to know the LaGrange formula? Although not covered in class, it is in Section 1.6, which we've been asked to read.

The test material will only be announced on Tuesday. --Drorbn 13:02, 14 October 2006 (EDT)

For question 28: "Let V be a finite-dimensional vector space over C with dimension n. Prove that if V is now regarded as a vector space over R, then dim V = 2n"... Is this a formally defined concept? (that is, while it is obvious what they mean, how could you state it rigorously)

${\mathbb {R} }$ is a subset of ${\mathbb {C} }$, so if you know how to multiply by scalars in ${\mathbb {C} }$, you automatically know how to multiply by scalar in ${\mathbb {R} }$. Thus every vector space over ${\mathbb {C} }$ is also a vector space over ${\mathbb {R} }$ (and in the same way, also over ${\mathbb {C} }$). --Drorbn 22:01, 14 October 2006 (EDT)