Let a be real symmetric and positive semidefinite. let α1 ≤ · · · ≤ αn be the eigenvalues of a. show that for any nonzero vector x ∈ rn, we have α1 ≤ ila xll / xll ≤ αn.

What is the probability of drawing three queens from a standard deck of cards, given that the first card drawn was a queen? assume that the cards are not replaced.

What are “like terms”? why can we only add like terms?

Si la base de un triángulo isósceles mide 70 m y el ángulo opuesto a ésta mide 58°; entonces ¿cuánto mide la altura de dicho triángulo? a) 21.87 m. b) 40.01 m. c) 43.74 m. d) 63.14 m.