- #1

jrevard

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## Homework Statement

Consider a cube whose edges are each of unit length. One corner coincides with the origin of an xyz Cartesian coordinate system. Three of the cube's edges extend from the origin along the positive direction of each coordinate axis. Find the vector that begins at the origin and extends

(a) along a major diagonal of the cube;

(b) along the diagonal of the lower face of the cube.

(c) Calling these vectors A and B, find C = A x B.

(d) Find the angle between A and B

## Homework Equations

cos(theta) = (A dot B)/(|A||B|)

## The Attempt at a Solution

I get cos(theta) = 2/(root(6)),

they get cos(theta) = (1-1)/(root(6)) = 0