Vectors 向量

dot product / scalar product / inner product / projection product 點積/內積/純量積 a·b
A·B = |A| |B| cos(θ)
A_B = |A| cos(θ)

For vectors a = (a₁, a₂, ..., a_n) and b = (b₁, b₂, ..., b_n) ,

a·b = a₁b₁ + a₂b₂ + ... + a_nb_n

For example, vectors a = (1, 2, 3) and b = (0, 4, 5),

a·b = 1×0 + 2×4 + 3×5 = 23

Matlab code:

>> a = [1 2 3];
>> b = [0 4 5];
>> dot(a,b)

ans =

    23

cross product/vector product 點積/向量積 a×b

參考資料

內積與外積