Is the line through (4,1,-1) and (2,5,3) parallel to the line through (-3,2,0) and (5,1,4)?
The Attempt at a Solution
Line one 'direction' = (-2,4,4) = A
Line two 'direction' = (8,-1,4) = B
I remember that the cross product of two vectors is zero if they are parallel, but AxB is not the zero vector; the answer in the book says they are indeed parallel...
Is this not the right method?