hw3: done 1,2,3,4,5a,6

hw3/hw3.tex

@@ -268,7 +268,7 @@ $$A_{1,1} = A_{1,1}^T$$
 
 and thus $A_{1,1}$ is shown to be symmetric.
 
-Then, since $A$ is positive definite, $ > 0$ for any vector $x \in R^n$. We choose a vector $x$ such that $x_k = 0$ for any $p < k \leq n$.
+Then, since $A$ is positive definite, $x^TAx > 0$ for any vector $x \in R^n$. We choose a vector $x$ such that $x_k = 0$ for any $p < k \leq n$.
 
 Then: