1. Determine whether the vectors [2,-1] and [-2,-5] are orthogonal.
I remember learning this stuff last year and I think it has something to do with the dot product of vectors maybe? Help would be greatly appreciated.
2. Find the angle between vector u = [-2, 5] and vector v= [-1, 3].
Once again, I completely forget how to do this. Cross product?
If this is the case, could you not also solve this problem by calculating then comparing the slope of both vectors as lines?
since , vectors are not orthogonal.
Is this approach correct?