a vector in the direction from A to B is C = B-A = 2i + (b-2)j
The unit vector c = C/|C| = 2/√(b^2-4b+8) i + (b-2)/√(b^2-4b+8) j
If |C| = 2, then b^2-4b+8 = 4 or b = 2
Or, since |2i + (b-2)j|=2, b-2 must be zero
1) The position vectors of A and B are OA= -i+2j+k and OB = i+bj+k respectively.
a) Find ,in terms of b, the unit vector in the direction of AB
b) Given AB = 2, find the value of b.
1 answer
1 answer