The Cross Product of Two Vectors

So you get the determinant of i, j, k, and then you write 1, 2, 3, 4, 5, 6 over here. These numbers I'm referring to, and the determinant of this matrix will give you the cross product of two vectors. This row, so start by this i, you cross out whatever touches i, both columns and rows. You get 2, 3, 5, and 6. Minus j, whatever touches i and j, you close it off and you write the rest, 1, 3, 4, 6. And plus k of closed off, so I'm left with this. If you remember calculating determinant of a 2 by 2, so these two diagonal multiplication minus this, always. Okay, so I'll repeat this three times. I'm not going to show you the details, but i times 2 times 6 minus 5 times 3, so you get it yourself. Minus 3i plus 6j minus 3k.