Question

6. Find the cross product u x v
u=i-7k, v=j+k

Answer 1

The easiest way to find a cross product is to evaluate the determinant. Take the coefficients of i, j and k for u and v as and put them in a determinant form like this:

\[\left| \begin{matrix} i & j & k \\ 1 & 0 & -7\\ 0 & 1 & 1 \ \end{matrix} \right|\]

Can you evaluate the determinant now?

Answer 2

i + 6j ?

Answer 3

No it evaluates to 7i - j + k