Vector (What's Wrong?)

correct: |i × j| = | i || j | sinθ = (1)(1)sin90° = 1
wrong: i × j = | i || j | sinθ = (1)(1)sin90° = 1
correct: i × j = k

Notice that |i × j| and i × j are two different thing,
i × j is a vector, |i × j| is the length of the vector.
therefore DO NOT get confuse with the formula.

2012-07-11 11:34:21 補充：
yes, i ∙ j = | i || j |cosθ = (1)(1)cos90° = 0 is correct
since i . j is a scarlar product, it represents a constant number.

i x j is a vector, not a scalar. So its magnitude is 1, but its direction is k. That is why i x j = k.