Question

If vector a = 3i - j - 2k and vector b = 2i + 3j + k, find (a + 2b) x (2a - b).

Answer 1

Given  \(\vec a=3\hat i-\hat j-2\hat k\) and  \(\vec b=2\hat i+3\hat j+\hat k\)

We need to find the vector  \((\vec a+2\vec b)\times(2\vec a-\vec b).\)

Recall the cross product of two vectors

Here, we have (a₁, a₂, a₃) = (7, 5, 0) and (b₁, b₂, b₃) = (4, –5, –5)