R - Compute Cross Product of Vectors (Physics)

Question

What am I doing wrong?

> crossprod(1:3,4:6)
     [,1]
[1,]   32

According to this website:http://onlinemschool.com/math/assistance/vecto

Answer 1

You can try expand.grid

expand.grid(LETTERS[1:3],letters[1:3])

Output:

 Var1 Var2
1    A    a
2    B    a
3    C    a
4    A    b
5    B    b
6    C    b
7    A    c
8    B    c
9    C    c