Question

Find vector (p * q), if vector p = 2i - 4j +7k and vector q = 3i - 2j +2k

Answer 1

p x q = \(\begin{vmatrix}\hat i&\hat j&\hat k\\2&-4&7\\3&-2&2\end{vmatrix}\) 

= \(\hat i\) (-4 x 2 - (-2) x 7) - \(\hat j\) (2 x 2 - 3 x 7) + \(\hat k\)(2 x -2 - 3 x -4)

 = \(\hat i\)(-8 - 14) - \(\hat j\) (4 - 21) + \(\hat k\) (-4 + 12)

 = 6 \(\hat i\) + 17\(\hat j\) + 8 \(\hat k\)