1. Section 3.3 – The Cross Product
Unit 3 – Vectors
Section 3.3 – The Cross Product
Calculator Required

2. Vocabulary First (Again  )
Determinant – a number (scalar)
Notations
The 2 x 2 Determinant

3. Try these four…
…and these four

4. The MINOR of a matrix
Cross out the row and column of the element
Compute the determinant of what remains

5. The 3 x 3 Determinant
1. Select ANY row or column (most zeros would be smart)
2. Take each element and multiply it by its MINOR.
Apply (to be explained). Remember the + starts
with the first row first column element. –

6. –
– –
– –

7. – – –
= 0

8. Definition
The cross product of two vector yields a vector which
Is orthogonal to the two given vectors.
If A = ai + bj + ck and B = di + ej + fk

9. Find the vector orthogonal to A = 2i + 3j + k and B = 3i - 2j + 5k

10. Find the vector orthogonal to A = 7i + 1j + 2k and B = i + 3j + 4k