Given vectors u= (3, -4, 1) and v= (2, 1, -5)

Question

Find:

a) u x v
b)|u x v|

Answer 1

you should have learned some type of algorithm or method of finding the cross product.

About 2/3 of the way down this page is good illustration of a method

http://www.ltcconline.net/greenl/Courses/107/vectors/dotcros.htm

I got u x v = [19,17,11)

you can check this to be correct by taking the dot product with each of the original vectors, it is correct.
then | [19,17,11) |
= √(361+289+121) = √771