⑴a+b =; ⑵a-b =;
⑶λa =; ⑷ a b=
How to prove the above algorithm? (Just substitute A = I+J+K and B = I+J+K)
2. How to find the coordinates of a space vector? (The coordinates representing the end of the directed line segment of this vector minus the coordinates of the starting point. )
3. Exercise: (1) The coordinate of a vector parallel to the vector (1,-3,2) is (c).
A.( 1,3,2) B.(- 1,-3,2) C.(-2,6,-4) D.( 1,-3,-2)
(2) Given point A (1, 2,-1), vector OC and vector OA are symmetric about plane xoy, and vector OB and vector OA are symmetric about plane X, find the vector sum.
Answer: = (0,4,0) = (0,4,2)
(3) Known vector =(2,-1, 3) Find a vector so that ∨ and ∣ ∣ = 3 ∣.
Answer: =(6,-3,9) or = (-6,3,5)
(4) Given three points A (- 1, 0,2), B (- 1, 1, 2) and C (-3,0,4), let =, =,
If K+ and k -2 are perpendicular to each other, find the value of k. (K=2 or k =-)